fix: rename listener using its address and port

[zhaohuabing]

Currently, the xDS listener is named after one of the owning Gateway Listeners. When multiple Gateway Listeners are configured listening on the same port, the generated xDS listener name is derived from a randomly selected Gateway Listener. This can cause unnecessary listener drains in Envoy if one of the Gateway Listeners is deleted or a new one is created using the same port.

This PR resolves the issue by naming the xDS listener based on its listening address and port, ensuring consistent naming even when multiple Gateways share the same port.

Notice: xDS listener is a de-fact API surface - it's used by EnvoyPatchPolicy and ExtensionManager to modify xDS resources, and users may rely on it for configuring metrics or monitoring. To avoid introducing breaking change in v1.5 ,this change is gated by the UseAddressAsListenerName feature flag. This flag is disabled by default in v1.5, and it will be enabled in v1.6.

This PR also:

• Changes the UDP listener name to follow the same naming patter as TCP.
• Adds Gateway Resource to the Listener metadata, so the ExtensionManager can use them as a replacement of the previous listener name if the Gateway and Listener resource names are required in its mutation processing.

fix: #6534
release-note: yes

[codecov]

Codecov Report

Attention: Patch coverage is 56.75676% with 16 lines in your changes missing coverage. Please review.

Project coverage is 70.78%. Comparing base (9b91cd1) to head (117a25f).

Files with missing lines	Patch %	Lines
api/v1alpha1/envoygateway_helpers.go	28.57%	9 Missing and 1 partial ⚠️
internal/xds/translator/listener.go	75.00%	2 Missing and 1 partial ⚠️
internal/xds/translator/metadata.go	66.66%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6544      +/-   ##
==========================================
+ Coverage   70.77%   70.78%   +0.01%     
==========================================
  Files         224      224              
  Lines       38614    38672      +58     
==========================================
+ Hits        27328    27375      +47     
- Misses       9695     9703       +8     
- Partials     1591     1594       +3     

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[zhaohuabing]

/retest