[release/v1.2] cherry pick bug fixes and IPv6 to v1.2.2

[zhaohuabing]

• fix: tcp listener is rejected when no route attached (fix: tcp listener is rejected when no route attached #4681)
• fix: remove backendrefs validation (fix: remove backendrefs validation #4705)
• fix: translator reports errors for existing clusters and secretes (fix: translator reports errors for existing clusters and secretes #4707)
• xds: always use :: and IPv4Compact for dynamic listener (xds: always use :: and IPv4Compact for dynamic listener #4743)
• fix: frequent 503 errors when connecting to a Service experiencing high Pod churn (Fix: frequent 503 errors when connecting to a Service experiencing high Pod churn #4754)
• xds: use V4_PREFERRED dnsLookupFamily by default (xds: use V4_PREFERRED dnsLookupFamily by default #4745)

[codecov]

Codecov Report

Attention: Patch coverage is 79.24528% with 11 lines in your changes missing coverage. Please review.

Project coverage is 65.58%. Comparing base (8a03f39) to head (4dfff09).
Report is 1 commits behind head on release/v1.2.

Files with missing lines	Patch %	Lines
internal/gatewayapi/securitypolicy.go	78.04%	6 Missing and 3 partials ⚠️
internal/cmd/envoy/shutdown_manager.go	0.00%	2 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v1.2    #4765      +/-   ##
================================================
+ Coverage         65.55%   65.58%   +0.03%     
================================================
  Files               211      211              
  Lines             31943    31974      +31     
================================================
+ Hits              20939    20969      +30     
- Misses             9760     9763       +3     
+ Partials           1244     1242       -2     

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