Fixes (web): Optimized search page style and functionality #3221 (#9627)

### What problem does this PR solve?

Fixes (web): Optimized search page style and functionality #3221

- Updated search page and view title styles
- Modified dataset list and multi-select control styles
- Optimized text field and button styles
- Updated filter button icons
- Adjusted metadata filter styles
- Added default descriptions for the smart assistant

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/next-search/search-setting-aisummery-config.tsx

@@ -113,7 +113,7 @@ export function LlmSettingFieldItems({
             <FormControl>
               <SelectWithSearch
                 options={options || modelOptions}
-                triggerClassName="bg-bg-card"
+                triggerClassName="!bg-bg-input"
                 {...field}
               ></SelectWithSearch>
             </FormControl>