[v23.3.x] raft: don't promote to voter if previous config is not committed

[vbotbuildovich]

Backport #17675 to branch v23.3.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 v23.3.x
git checkout -b vbotbuildovich/backport-17675-v23.3.x-34
git cherry-pick -x b1e1e0298b4e2da7985bd43f15739852191a46ff ccb5f640f10a373f99e95daeab42d801ceefd469 1085f755a575f0baffb072059c22859e0040142a eb8218558514bba1c0533a5f028d93c7d32d6a6c cea0c6c85f7a56eaef603d8fbc7a69d3ebb923c0

git push origin vbotbuildovich/backport-17675-v23.3.x-34
gh pr create \
  --title "[v23.3.x] raft: don't promote to voter if previous config is not committed" \
  --base "v23.3.x" \
  --label "kind/backport" \
  --head "vbotbuildovich/backport-17675-v23.3.x-34" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --milestone "v23.3.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/17675 "

JIRA Link: [CORE-2323](https://redpandadata.atlassian.net/browse/CORE-2323)

[ztlpn]

fixed by the linked pr