[v26.1.x] rpk: bumping deprecated dependencies and go fix

[vbotbuildovich]

Backport #30115 to branch v26.1.x. This issue was created as a placeholder because the original PR's commit(s) could not be automatically cherry-picked.
Here are the commands to execute:

git checkout v26.1.x
git checkout -b manual-backport-30115-v26.1.x-629
git cherry-pick -x ba5fe0aa89 87d800b5fc e40deed10c

git push origin manual-backport-30115-v26.1.x-629
gh pr create \
  --title "[v26.1.x] rpk: bumping deprecated dependencies and go fix" \
  --base "v26.1.x" \
  --label "kind/backport" \
  --head "manual-backport-30115-v26.1.x-629" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --milestone "v26.1.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/30115 "