router: remove send_local_reply_when_no_buffer_and_upstream_request guard

[botengyao]

Commit Message: router: remove send_local_reply_when_no_buffer_and_upstream_request guard Risk Level: low Testing: unit test Docs Changes: Fixes #36609

[repokitteh-read-only[bot]]

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!

:cat:

Caused by: https://github.com/envoyproxy/envoy/pull/36620 was opened by botengyao.

see: more, trace.

[repokitteh-read-only[bot]]

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

:cat:

Caused by: https://github.com/envoyproxy/envoy/pull/36620 was opened by botengyao.

see: more, trace.

[botengyao]

/assign @alyssawilk

[botengyao]

/retest

[alyssawilk]

/retest