feat: upgrade ai package to version six and the corresponding @ai-sdk/* packages to compatible versions (#18172)

Used the migration guide to carry out this upgrade:
https://ai-sdk.dev/docs/migration-guides/migration-guide-6-0

I have not been able to test locally due to credits.

<img width="220" height="450" alt="image"
src="https://github.com/user-attachments/assets/050b34b9-3239-4010-8c47-b43d44571994"
/>

---------

Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-front/src/modules/ai/utils/isThinkingStepPart.ts

@@ -1,4 +1,4 @@
-import { isToolUIPart } from 'ai';
+import { isStaticToolUIPart } from 'ai';
 import { type ExtendedUIMessagePart } from 'twenty-shared/ai';
 
 import { type ThinkingStepPart } from '@/ai/utils/thinkingStepPart';
@@ -10,5 +10,5 @@ export const isThinkingStepPart = (
     return true;
   }
 
-  return isToolUIPart(part) && part.type !== 'tool-code_interpreter';
+  return isStaticToolUIPart(part) && part.type !== 'tool-code_interpreter';
 };