[v24.1.x] r/consensus: use term from snapshot when it is available at startup

[vbotbuildovich]

Backport #23835 to branch v24.1.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 v24.1.x
git checkout -b vbotbuildovich/backport-23835-v24.1.x-258
git cherry-pick -x 65068aa37b bf10ec4c5c ceea064eeb

git push origin vbotbuildovich/backport-23835-v24.1.x-258
gh pr create \
  --title "[v24.1.x] r/consensus: use term from snapshot when it is available at startup" \
  --base "v24.1.x" \
  --label "kind/backport" \
  --head "vbotbuildovich/backport-23835-v24.1.x-258" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --milestone "v24.1.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/23835 "