refactor(ui): update knowledge graph, chunk, metadata, agent log styles (#13518)

### What problem does this PR solve?

Update UI styles:
- **Dataset** > **Knowledge graph** tooltip
- **Dataset** > **Files** > **Manage metadata** modal
- **Dataset** > **Files** > **Modify Chunking Method** > **Auto
metadata** > **Manage generation settings** modal
- **Agent** > **Canvas (Ingestion pipeline)** > **Dataflow result**

### Type of change

- [x] Refactoring

web/src/less/mixins.less

@@ -17,8 +17,8 @@
   caption {
     color: @blurBackground;
     font-size: 14px;
-    height: 20px;
-    line-height: 20px;
+    // height: 20px;
+    line-height: 1.25;
     font-weight: 600;
     margin-bottom: 6px;
   }