Added semi-automatic mode to the metadata filter (#11886)

### What problem does this PR solve?

Retrieval metadata filtering adds semi-automatic mode, and users can
manually check the metadata key that participates in LLM to generate
filter conditions.
### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/locales/en.ts

@@ -737,11 +737,13 @@ This auto-tagging feature enhances retrieval by adding another layer of domain-s
       metadataTip:
         'Metadata filtering is the process of using metadata attributes (such as tags, categories, or access permissions) to refine and control the retrieval of relevant information within a system.',
       conditions: 'Conditions',
+      metadataKeys: 'Filterable items',
       addCondition: 'Add condition',
       meta: {
         disabled: 'Disabled',
         auto: 'Automatic',
         manual: 'Manual',
+        semi_auto: 'Semi-automatic',
       },
       cancel: 'Cancel',
       chatSetting: 'Chat setting',