fix: Improve feedback messages when adding users already in room

[harii55]

This PR fixes misleading success messages shown when attempting to add users who are already members of a room. Previously, the system would always display "The users have been added" even when no users were actually added, creating user confusion.

Proposed changes (including videos or screenshots)

This is how it looks like after changes.

Issue(s)

Closes #24701

Steps to test or reproduce

1. Go to any room
2. Click on members
3. Click on add users (withadmin access of the room)

Further comments

[dionisio-bot]

Looks like this PR is not ready to merge, because of the following issues:

• This PR is missing the 'stat: QA assured' label
• This PR is missing the required milestone or project

Please fix the issues and try again

If you have any trouble, please check the PR guidelines

[changeset-bot]

⚠️ No Changeset found

Latest commit: 1857e25

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[coderabbitai]

Important

Review skipped

Draft detected.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}