fix(blocks): add json_schema_extra for images field to prevent frontend crash

When clicking '+ Item' on the Images input field, the frontend was crashing with:
TypeError: Cannot read properties of undefined (reading 'type')

This was caused by the frontend not being able to determine what type of items
to add to the Optional[List[MediaFileType]] array. Added explicit JSON schema
with array type and string items with URI format to provide the frontend with
the necessary type information.

Co-authored-by: Bently <Bentlybro@users.noreply.github.com>

autogpt_platform/backend/backend/blocks/ai_image_customizer.py

@@ -64,6 +64,10 @@ class AIImageCustomizerBlock(Block):
             description="List of input images (optional)",
             default=None,
             title="Images",
+            json_schema_extra={
+                "type": "array",
+                "items": {"type": "string", "format": "uri"},
+            },
         )
         output_format: OutputFormat = SchemaField(
             description="Format of the output image",