🧵 fix: Remove Empty String values from Gemini API Payload (#11213)

When users don't explicitly set `maxOutputTokens` in Google/Gemini endpoint
settings, LibreChat was sending `"maxOutputTokens": ""` instead of omitting
the field. This caused issues with Gemini SDK and AI reverse proxies that
expect numeric types.

Changes:
- Add `removeEmptyStrings=true` to `removeNullishValues()` in googleSchema
- Add `removeEmptyStrings=true` to `removeNullishValues()` in compactGoogleSchema
- Add `removeEmptyStrings=true` to `removeNullishValues()` in getGoogleConfig()
- Create comprehensive test suite for Google endpoint (45 tests)

The fix ensures empty strings for numeric fields like maxOutputTokens,
temperature, topP, and topK are properly removed from the request payload.

Closes #11187

packages/data-provider/src/schemas.ts

@@ -903,7 +903,7 @@ export const googleBaseSchema = tConversationSchema.pick({
 });
 
 export const googleSchema = googleBaseSchema
-  .transform((obj: Partial<TConversation>) => removeNullishValues(obj))
+  .transform((obj: Partial<TConversation>) => removeNullishValues(obj, true))
   .catch(() => ({}));
 
 /**
@@ -1101,7 +1101,7 @@ export const compactGoogleSchema = googleBaseSchema
       delete newObj.topK;
     }
 
-    return removeNullishValues(newObj);
+    return removeNullishValues(newObj, true);
   })
   .catch(() => ({}));