feat: grpc-only mode (backport #11430)

[mergify]

This is an automatic backport of pull request #11430 done by Mergify.
Cherry-pick of 1880a7d has failed:

On branch mergify/bp/release/v0.45.x/pr-11430
Your branch is up to date with 'origin/release/v0.45.x'.

You are currently cherry-picking commit 1880a7d17.
  (fix conflicts and run "git cherry-pick --continue")
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  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   CHANGELOG.md
	both modified:   server/start.go

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[lgtm-com]

This pull request introduces 3 alerts when merging 91287cf into 160a103 - view on LGTM.com

new alerts:

• 2 for Useless assignment to local variable
• 1 for Unreachable statement

[lgtm-com]

This pull request introduces 1 alert when merging 23a77ae into 160a103 - view on LGTM.com

new alerts:

• 1 for Useless assignment to local variable

[lgtm-com]

This pull request introduces 1 alert when merging bf37af4 into 7997b26 - view on LGTM.com

new alerts:

• 1 for Useless assignment to local variable