fix: timeout risk in ai-content-moderation

[shreemaan-abhishek]

Description

When the region is not configured (globally) the aws client falls back to using IDMS endpoint to load aws config. In some CI environments, the IDMS endpoint configured in lua-resty-aws might not be available which could lead to timeout errors in CI.

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)