[8.10] fix: add back gzip support for grpc otlp endpoint (backport #11434)

[mergify]

This is an automatic backport of pull request #11434 done by Mergify.
Cherry-pick of cfce80b has failed:

On branch mergify/bp/8.10/pr-11434
Your branch is up to date with 'origin/8.10'.

You are currently cherry-picking commit cfce80b6.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   internal/beater/beater.go
	modified:   systemtest/otlp_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   changelogs/head.asciidoc

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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[mergify]

This pull request has not been merged yet. Could you please review and merge it @kruskall? 🙏

[lahsivjar]

Force pushed to sign all commits.