tcp_proxy: fix OD-CDS over ADS

[adisuissa]

Commit Message: tcp_proxy: fix OD-CDS over ADS
Additional Description:
This PR is similar to #41174 (and uses the same component to achieve the same goal).
The fix allows proper use of tcp_proxy on-demand cluster discovery when used over ADS.

Risk Level: low - only impacts OD-CDS over tcp_proxy
Testing: Added integration tests.
Docs Changes: N/A
Release Notes: Added
Platform Specific Features: N/A
Runtime guard: Added envoy.reloadable_features.tcp_proxy_odcds_over_ads_fix to disable the behavior.

[repokitteh-read-only]

As a reminder, PRs marked as draft will not be automatically assigned reviewers,
or be handled by maintainer-oncall triage.

Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #43529 was opened by adisuissa.

see: more, trace.

[repokitteh-read-only]

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

🐱

Caused by: #43529 was ready_for_review by adisuissa.

see: more, trace.

[adisuissa]

Assigning the same maintainers from #41174 and a senior-maintainer
/assign @KBaichoo @nezdolik @botengyao