refactor: potential undefined access in getwebpackconfigpath

The function accesses `builder.options?.configPath` without verifying `builder.options` exists. While optional chaining prevents a crash, if `builder.options` is undefined, `webpackPath` becomes undefined and is returned — but the caller may expect a valid path. This can lead to runtime errors downstream when the path is used (e.g., in file system operations or webpack CLI invocation).

Signed-off-by: Zendy <50132805+zendy199x@users.noreply.github.com>

Author: zendy199x

lib/compiler/helpers/get-webpack-config-path.ts

@@ -1,3 +1,4 @@
+```ts
 import { Input } from '../../../commands';
 import { Builder, Configuration } from '../../configuration';
 import { getValueOrDefault } from './get-value-or-default';
@@ -31,9 +32,15 @@ export function getWebpackConfigPath(
     appName,
   );
 
-  webpackPath =
-    typeof builder === 'object' && builder?.type === 'webpack'
-      ? builder.options?.configPath
-      : undefined;
-  return webpackPath;
+  if (typeof builder === 'object' && builder?.type === 'webpack') {
+    const webpackConfigPath = builder.options?.configPath;
+    if (webpackConfigPath) {
+      return webpackConfigPath;
+    }
+    // If builder.type is 'webpack' but no config path is specified, return undefined
+    // to let webpack use its default behavior
+    return undefined;
+  }
+  return undefined;
 }
+```