fix(typo): use the correct bing name for ai-search.

[maratrixx]

Ⅰ. Describe what this PR did

The ai-search plugin is using the wrong bing engine name, I tried to fix it again.

Ⅱ. Does this pull request fix one issue?

None

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

needReference: true
referenceFormat: "### 数据来源\n%s"
searchFrom:
- type: bing        // note here.
  apiKey: "your-bing-key"
  serviceName: "search-service.dns"
  servicePort: 8080

Ⅴ. Special notes for reviews

[CLAassistant]

All committers have signed the CLA.

[cr7258]

@maratrixx Please sign the Contributor License Agreement.

[maratrixx]

@maratrixx Please sign the Contributor License Agreement.

Signed.

[CH3CHO]

LGTM

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.41%. Comparing base (ef31e09) to head (8c4c218).
Report is 310 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1807      +/-   ##
==========================================
+ Coverage   35.91%   43.41%   +7.50%     
==========================================
  Files          69       76       +7     
  Lines       11576    12278     +702     
==========================================
+ Hits         4157     5331    +1174     
+ Misses       7104     6617     -487     
- Partials      315      330      +15     

see 71 files with indirect coverage changes