fix not programmed listeners for merge gateways

[cnvergence]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.44%. Comparing base (cab6837) to head (b6f678d).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8744      +/-   ##
==========================================
+ Coverage   74.39%   74.44%   +0.04%     
==========================================
  Files         246      246              
  Lines       39221    39223       +2     
==========================================
+ Hits        29180    29199      +19     
+ Misses       8017     8003      -14     
+ Partials     2024     2021       -3     

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[chatgpt-codex-connector]

Exclude non-ready listeners from TLS overlap checks

In merge-gateways mode this new continue drops non-programmed listeners from xDS generation, but checkOverlappingTLSConfig still iterates all HTTPS listeners from gateway.listeners (including non-ready ones) and can set TLSOverlaps on ready listeners. That causes internal/xds/translator/listener.go to force ALPN to http/1.1 for a listener that no longer has any overlapping peer in xDS, so valid HTTPS listeners can lose HTTP/2 unnecessarily whenever an overlapping listener is invalid/unprogrammed.

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