feat: support bypassing envoy overload manager for listeners

[rudrakhp]

What type of PR is this?

feat: support bypassing envoy overload manager for listeners
Also has a minor refactor of Listener IR struct that resolves a TODO.

What this PR does / why we need it:

To enable user to bypass overload manager for listeners. See #5260 for more details.

Which issue(s) this PR fixes:

Fixes #5260

Release Notes: Yes/No

[codecov]

Codecov Report

Attention: Patch coverage is 85.91549% with 10 lines in your changes missing coverage. Please review.

Project coverage is 65.25%. Comparing base (12336d8) to head (316f332).

Files with missing lines	Patch %	Lines
internal/gatewayapi/clienttrafficpolicy.go	77.41%	5 Missing and 2 partials ⚠️
internal/xds/translator/translator.go	33.33%	0 Missing and 2 partials ⚠️
internal/xds/translator/listener.go	93.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5441      +/-   ##
==========================================
- Coverage   65.34%   65.25%   -0.09%     
==========================================
  Files         213      213              
  Lines       33915    33920       +5     
==========================================
- Hits        22162    22136      -26     
- Misses      10426    10450      +24     
- Partials     1327     1334       +7     

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[rudrakhp]

Was wondering if we should have CoreListenerDetails nested under TCPBasedListenerDetails, hierarchically it's correct but might be confusing.

[arkodg]

can you explain this use case @rudrakhp ? im not sure why its required ? if a proxy is overloaded, we do want the health checks enabled on the listener to fail so the fronting LB can send new requests to another proxy w/o affecting existing requests/connections

[rudrakhp]

From the conversation in the original issue, I was under the impression we do support custom health check probes, that might require users to set this option in custom listeners for these probes as well. Do correct me if this is not the case.