fix(typescript): accept empty list of suggested prompts for the assistant class (#2650)

Author: zimeg

src/Assistant.ts

@@ -46,7 +46,7 @@ type SetSuggestedPromptsFn = (
 
 interface SetSuggestedPromptsArguments {
   /** @description Prompt suggestions that appear when opening assistant thread. */
-  prompts: [AssistantPrompt, ...AssistantPrompt[]];
+  prompts: AssistantPrompt[];
   /** @description Title for the prompts. */
   title?: string;
 }

test/types/assistant.test-d.ts

@@ -1,3 +1,4 @@
+import type { AssistantThreadsSetSuggestedPromptsResponse } from '@slack/web-api';
 import { expectError, expectType } from 'tsd';
 import { type AllAssistantMiddlewareArgs, Assistant } from '../../src/Assistant';
 import type { AssistantThreadContext } from '../../src/AssistantThreadContextStore';
@@ -33,8 +34,13 @@ expectType<Assistant>(
 // threadStarted tests
 new Assistant({
   userMessage: asyncNoop,
-  threadStarted: async ({ saveThreadContext }) => {
+  threadStarted: async ({ saveThreadContext, setSuggestedPrompts }) => {
     expectType<void>(await saveThreadContext());
+    expectType<AssistantThreadsSetSuggestedPromptsResponse>(
+      await setSuggestedPrompts({
+        prompts: [],
+      }),
+    );
     return Promise.resolve();
   },
 });