[v23.1.x] cloud_storage: Unknown STM command handling

[vbotbuildovich]

Backport #12001 to branch v23.1.x. Note that this issue was created as a placeholder, since the original PR's commit(s) could not be automatically cherry-picked.
Here are the commands to execute:

git checkout v23.1.x
git checkout -b vbotbuildovich/backport-12001-v23.1.x-816
git cherry-pick -x a78ac8c44b3ad518c2ec16d043e39b32e2b06ed3

git push origin vbotbuildovich/backport-12001-v23.1.x-816
gh pr create \
  --title "[v23.1.x] cloud_storage: Unknown STM command handling" \
  --base "v23.1.x" \
  --label "kind/backport" \
  --head "vbotbuildovich/backport-12001-v23.1.x-816" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --reviewer "jcsp" \
  --milestone "v23.1.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/12001 "

[piyushredpanda]

Merged already