test(ai-aliyun-content-moderation): remove unused mock LLM location

[janiussyafiq]

Description

The location /v1/chat/completions block on the mock server at port 6724 in t/plugin/ai-aliyun-content-moderation.t is never reached by any of the 44 test blocks (130 subtests) in the file.

Every test that needs an upstream LLM points ai-proxy's override endpoint to either:

• 127.0.0.1:1980 (the shared X-AI-Fixture test fixture mock), or
• localhost:7737 (the sse_server_example Go process started by ci/common.sh)

No test points an upstream endpoint at port 6724. Port 6724 is only used as the Aliyun content moderation API mock, which is served by location /. The /v1/chat/completions block is dead code left over from an earlier shape of the test.

Removing it keeps the mock focused on the Aliyun moderation API and reduces noise for future readers.

Verification

Ran the full test file locally before and after the change with sse_server_example listening on port 7737:

• Before: 130 subtests pass
• After: 130 subtests pass

No behavior change; pure cleanup.

Which issue(s) this PR fixes:

Fixes #

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)