fix(translator): Re-fill client certificates of services after merging certificate

[randmonkey]

What this PR does / why we need it:

Re-fill the client certificate of Kong Services after merging certificates to prevent service referring to non-exist client certificates.

Which issue this PR fixes:

fixes #6223

Special notes for your reviewer:

PR Readiness Checklist:

Complete these before marking the PR as ready to review:

• [x] the CHANGELOG.md release notes have been updated to reflect any significant (and particularly user-facing) changes introduced by this PR

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Please upload report for BASE (main@594fe56). Learn more about missing BASE report.

:exclamation: Current head 504cf88 differs from pull request most recent head 74b1aae

Please upload reports for the commit 74b1aae to get more accurate results.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #6228 +/- ## ====================================== Coverage ? 69.9% ====================================== Files ? 200 Lines ? 19909 Branches ? 0 ====================================== Hits ? 13920 Misses ? 5003 Partials ? 986 ```

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[team-k8s-bot]

The backport to release/2.12.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/2.12.x release/2.12.x
# Navigate to the new working tree
cd .worktrees/backport-release/2.12.x
# Create a new branch
git switch --create backport-6228-to-release/2.12.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 d410be40f1e93dbfd6a2c9c8421bbba0009ca378
# Push it to GitHub
git push --set-upstream origin backport-6228-to-release/2.12.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/2.12.x

Then, create a pull request where the base branch is release/2.12.x and the compare/head branch is backport-6228-to-release/2.12.x.