[CHERRY-PICK] fix(gc): redact redis_url_reg from GC extra attrs (#23134)

[chlins]

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Comprehensive Summary of your change

Cherry pick of #23134

Issue being fixed

Fixes #(issue)

Please indicate you've done the following:

• Well Written Title and Summary of the PR
• Label the PR as needed. "release-note/ignore-for-release, release-note/new-feature, release-note/update, release-note/enhancement, release-note/community, release-note/breaking-change, release-note/docs, release-note/infra, release-note/deprecation"
• Accepted the DCO. Commits without the DCO will delay acceptance.
• Made sure tests are passing and test coverage is added if needed.
• Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (release-2.15.0@72206bf). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/server/v2.0/handler/model/gc.go	0.00%	8 Missing ⚠️
src/server/v2.0/handler/gc.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                @@
##             release-2.15.0   #23141   +/-   ##
=================================================
  Coverage                  ?   65.98%           
=================================================
  Files                     ?     1074           
  Lines                     ?   116665           
  Branches                  ?     2941           
=================================================
  Hits                      ?    76986           
  Misses                    ?    35405           
  Partials                  ?     4274           

Flag	Coverage Δ
unittests	65.98% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/server/v2.0/handler/gc.go	2.33% <0.00%> (ø)
src/server/v2.0/handler/model/gc.go	0.00% <0.00%> (ø)

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[wy65701436]

lgtm