Missing clear indication that a quiz has been saved successfully

[pcenov]

Observed behavior

Observed while regression testing the changes made in #12283:

1. When I save a quiz there's no snackbar confirmation 'Changes saved successfully'.

2. When I attempt to save a quiz with empty title I see the "There was a problem saving this quiz" message instead of seeing a message for the missing title. Also when I enter a title and click the 'Save' button the message "There was a problem saving this quiz" remains visible and the user has no idea that the quiz has actually been saved which is quite confusing.

2024-06-17_14-44-33.mp4

Expected behavior

Clear indication that the changes have been saved successfully.

Steps to reproduce the issue

1. Install the build from EQM: On first save, update the quiz's ID when redirecting #12283
2. Import the exercises from the QA channel.
3. Create a quiz and Save it.

Usage Details

Kolibri kolibri_0.16.2a0.dev0+git.1251.g46ab928a-0ubuntu1_all.deb
Windows 11, Ubuntu 22 - Chrome

[pcenov]

@radinamatic