Azure.ClientSdk.Analyzers_0.1.1-dev.20260129.1

Remove duplicate AZC0012 analyzer (#13726)

* Initial plan

* Remove AZC0012 analyzer and all references

Co-authored-by: m-nash <64171366+m-nash@users.noreply.github.com>

* Fix ErrorAnalyzers tests to match actual fallback message

Co-authored-by: m-nash <64171366+m-nash@users.noreply.github.com>

* Revert ErrorAnalyzers changes - keep AZC0012 support

Co-authored-by: m-nash <64171366+m-nash@users.noreply.github.com>

* Revert test files and documentation to original state

Co-authored-by: m-nash <64171366+m-nash@users.noreply.github.com>

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: m-nash <64171366+m-nash@users.noreply.github.com>