[v23.3.x] r/consensus: use term from snapshot when it is available at startup

[vbotbuildovich]

Backport #23835 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-23835-v23.3.x-137
git cherry-pick -x 65068aa37b bf10ec4c5c ceea064eeb

git push origin vbotbuildovich/backport-23835-v23.3.x-137
gh pr create \
  --title "[v23.3.x] r/consensus: use term from snapshot when it is available at startup" \
  --base "v23.3.x" \
  --label "kind/backport" \
  --head "vbotbuildovich/backport-23835-v23.3.x-137" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --milestone "v23.3.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/23835 "