Bug #1812430 - No success pop-up/ snackbar is displayed after adding manually a login

[gitstart]

The PR display an snackbar when a new login is added

Issue video

fnx-64-issue.webm

Demo video after fix

fnx-64-fix.webm

Pull Request checklist

• [ ] Tests: This PR includes thorough tests or an explanation of why it does not
• [x] Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• [ ] Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

QA

• [x] QA Needed

  To download an APK when reviewing a PR (after all CI tasks finished running):

1. Click on Checks at the top of the PR page.
2. Click on the firefoxci-taskcluster group on the left to expand all tasks.
3. Click on the build-debug task.
4. Click on View task in Taskcluster in the new DETAILS section.
5. The APK links should be on the right side of the screen, named for each CPU architecture.

GitHub Automation

Used by GitHub Actions. Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1812430

[firefoxci-taskcluster[bot]]

No Taskcluster jobs started for this pull request

```js The `allowPullRequests` configuration for this repository (in `.taskcluster.yml` on the default branch) does not allow starting tasks for this pull request. ```

[csadilek]

Hey @gitstart, Thank you so much for your contribution. It’s much appreciated. Unfortunately, we are in the process of moving this repository to firefox-android early next week, and won’t be able to review or land any PRs until after the migration. Please feel free to reopen a new PR against the new repo once migration is complete. You will have to clone the new repository and reapply your changes. Thank you again, and sorry for the inconvenience.

For more information, please see https://github.com/mozilla-mobile/fenix/issues/26855.