fix(knowledge_base): Unchecked metadata name length (#21454)

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/services/metadata_service.py

 class MetadataService:
     @staticmethod
     def create_metadata(dataset_id: str, metadata_args: MetadataArgs) -> DatasetMetadata:
+        # check if metadata name is too long
+        if len(metadata_args.name) > 255:
+            raise ValueError("Metadata name cannot exceed 255 characters.")
+
         # check if metadata name already exists
         if (
             db.session.query(DatasetMetadata)
 
     @staticmethod
     def update_metadata_name(dataset_id: str, metadata_id: str, name: str) -> DatasetMetadata:  # type: ignore
+        # check if metadata name is too long
+        if len(name) > 255:
+            raise ValueError("Metadata name cannot exceed 255 characters.")
+
         lock_key = f"dataset_metadata_lock_{dataset_id}"
         # check if metadata name already exists
         if (

web/app/components/datasets/metadata/hooks/use-check-metadata-name.ts

         }
       }
 
+      if (name.length > 255) {
+        return {
+          errorMsg: t(`${i18nPrefix}.tooLong`, { max: 255 }),
+        }
+      }
+
       return {
         errorMsg: '',
       }

web/i18n/en-US/dataset.ts

     checkName: {
       empty: 'Metadata name cannot be empty',
       invalid: 'Metadata name can only contain lowercase letters, numbers, and underscores and must start with a lowercase letter',
+      tooLong: 'Metadata name cannot exceed {{max}} characters',
     },
     batchEditMetadata: {
       editMetadata: 'Edit Metadata',