[js] Fix enhancements manifest issues found in code review

- back()/forward(): accept a context id instead of hard-coding an empty
  string; delegate to traverseHistory({ context, delta: ±1 })
- continueWithAuth: replace username!/password! non-null assertions with
  an explicit undefined guard that throws a descriptive error
- continueWithAuth: capture bidi.send() response and apply the same
  response['type'] === 'error' check as generated methods, preventing
  silent failures

Author: pujagani

javascript/selenium-webdriver/private/bidi_enhancements_manifest.json

@@ -9,8 +9,8 @@
     "excludeTypes": [],
     "excludeMethods": [],
     "extraMethods": {
-      "back": "  async back(): Promise<void> {\n    await this.traverseHistory({ context: '', delta: -1 } as BrowsingContextTraverseHistoryParameters)\n  }",
-      "forward": "  async forward(): Promise<void> {\n    await this.traverseHistory({ context: '', delta: 1 } as BrowsingContextTraverseHistoryParameters)\n  }",
+      "back": "  async back(context: BrowsingContextBrowsingContext): Promise<void> {\n    await this.traverseHistory({ context, delta: -1 })\n  }",
+      "forward": "  async forward(context: BrowsingContextBrowsingContext): Promise<void> {\n    await this.traverseHistory({ context, delta: 1 })\n  }",
       "getTopLevelContexts": "  async getTopLevelContexts(): Promise<BrowsingContextGetTreeResult> {\n    return this.getTree({})\n  }",
       "printPage": "  async printPage(params: BrowsingContextPrintParameters): Promise<BrowsingContextPrintResult> {\n    return this.print(params)\n  }"
     },
@@ -48,7 +48,7 @@
     "extraMethods": {
       "cancelAuth": "  async cancelAuth(requestId: NetworkRequest): Promise<void> {\n    await this.continueWithAuth({ request: requestId, action: 'cancel' } as NetworkContinueWithAuthParameters)\n  }",
       "continueWithAuthNoCredentials": "  async continueWithAuthNoCredentials(requestId: NetworkRequest): Promise<void> {\n    await this.continueWithAuth({ request: requestId, action: 'default' } as NetworkContinueWithAuthParameters)\n  }",
-      "continueWithAuth": "  async continueWithAuth(params: NetworkContinueWithAuthParameters): Promise<void>\n  /** @deprecated Pass a NetworkContinueWithAuthParameters object instead — will be removed in a future major version. */\n  async continueWithAuth(requestId: NetworkRequest, username: string, password: string): Promise<void>\n  async continueWithAuth(\n    paramsOrRequestId: NetworkContinueWithAuthParameters | NetworkRequest,\n    username?: string,\n    password?: string,\n  ): Promise<void> {\n    const params: NetworkContinueWithAuthParameters =\n      typeof paramsOrRequestId === 'string'\n        ? ({\n            request: paramsOrRequestId,\n            action: 'provideCredentials',\n            credentials: { type: 'password', username: username!, password: password! },\n          } as NetworkContinueWithAuthParameters)\n        : (paramsOrRequestId as NetworkContinueWithAuthParameters)\n    await this.bidi.send({\n      method: 'network.continueWithAuth',\n      params: params as unknown as Record<string, unknown>,\n    })\n  }",
+      "continueWithAuth": "  async continueWithAuth(params: NetworkContinueWithAuthParameters): Promise<void>\n  /** @deprecated Pass a NetworkContinueWithAuthParameters object instead — will be removed in a future major version. */\n  async continueWithAuth(requestId: NetworkRequest, username: string, password: string): Promise<void>\n  async continueWithAuth(\n    paramsOrRequestId: NetworkContinueWithAuthParameters | NetworkRequest,\n    username?: string,\n    password?: string,\n  ): Promise<void> {\n    let params: NetworkContinueWithAuthParameters\n    if (typeof paramsOrRequestId === 'string') {\n      if (username === undefined || password === undefined) {\n        throw new Error('username and password are required when calling continueWithAuth with a request id')\n      }\n      params = {\n        request: paramsOrRequestId,\n        action: 'provideCredentials',\n        credentials: { type: 'password', username, password },\n      } as NetworkContinueWithAuthParameters\n    } else {\n      params = paramsOrRequestId as NetworkContinueWithAuthParameters\n    }\n    const response = await this.bidi.send({\n      method: 'network.continueWithAuth',\n      params: params as unknown as Record<string, unknown>,\n    }) as Record<string, unknown>\n    if (response['type'] === 'error') {\n      throw new Error(`${response['error']}: ${response['message']}`)\n    }\n  }",
       "beforeRequestSent": "  /** @deprecated Use {@link onBeforeRequestSent} instead — will be removed in a future major version. */\n  async beforeRequestSent(callback: (params: NetworkBeforeRequestSentParameters) => void): Promise<void> {\n    await this.onBeforeRequestSent(callback)\n  }",
       "authRequired": "  /** @deprecated Use {@link onAuthRequired} instead — will be removed in a future major version. */\n  async authRequired(callback: (params: NetworkAuthRequiredParameters) => void): Promise<void> {\n    await this.onAuthRequired(callback)\n  }",
       "fetchError": "  /** @deprecated Use {@link onFetchError} instead — will be removed in a future major version. */\n  async fetchError(callback: (params: NetworkFetchErrorParameters) => void): Promise<void> {\n    await this.onFetchError(callback)\n  }",