fix(backend revision): Update patch column when removing revisions

[yamashush]

Component/Part

backend revision

Description

This PR fixes the following feature's bug.

  /**
   * @async
   * Purge revision history of a note.
   * @param {Note} note - the note to purge the history
   * @return {Revision[]} an array of purged revisions
   */
  async purgeRevisions(note: Note): Promise<Revision[]> {

If we delete all revisions except the latest one, we need to update the patch column of the latest one.

Steps

• Added implementation
• Added / updated tests
• I read the contribution documentation and
  made sure that:
  • My commits are signed-off to accept the DCO.
  • This PR targets the correct branch: master for 1.x & docs, develop for 2.x

Related Issue(s)

• feat(backend revision): add clean-up note revisions job #5349 (comment)

[ErikMichelson]

Sorry, that this took so long, being quite busy currently. I tested it and it works perfectly. Just some linting errors and another small thing.

Thanks for your contribution! :)

[yamashush]

@ErikMichelson Sorry for being so late 🙏
I've finished making the changes, so please review again 😄