upstream: set IP_BIND_ADDRESS_NO_PORT when bind port is 0

[404SkillNotFound]

Commit Message:
upstream: set IP_BIND_ADDRESS_NO_PORT for upstream_bind_config

Additional Description:
Automatically enable IP_BIND_ADDRESS_NO_PORT when upstream_bind_config binds
to a source IP with port 0. This defers ephemeral port allocation until
connect() and helps prevent ephemeral port exhaustion.

Risk Level:
Low

Testing:
Unit test

Docs Changes:
N/A

Release Notes:
Added changelog fragment.

Platform Specific Features:
Linux

[Optional Runtime guard:]
envoy.reloadable_features.upstream_bind_config_fix_port_exhaustion

[Optional Fixes #Issue]
Fixes #44747

[Optional Fixes commit #PR or SHA]
Builds on the approach used in #38288 and the earlier work in #44837.

[Optional Deprecated:]
N/A

[Optional API Considerations:]
N/A

[repokitteh-read-only]

CC @envoyproxy/runtime-guard-changes: FYI only for changes made to (source/common/runtime/runtime_features.cc).

🐱

Caused by: #45916 was opened by 404SkillNotFound.

see: more, trace.