Remove unnecessary success toast

[HenrikeW]

Related issue(s) and PR(s)

There was a success toast for saved custom names shown every time any changes were saved.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

List of changes made

• introduced state variable that tracks if any custom name has been changed
• when pressing "Save changes", an attempt to save custom names is only made if any custom name has changed
• There is only one Toast message for "All changes saved", no specific one about the names.
• If anything goes wrong in the save with either time entries or custom names, a generic failure message will be shown.

Testing

• Try to make some changes and save

Definition of Done checklist

• I have made an effort making the commit history understandable
• I have performed a self-review of my own code and commented any hard-to-understand areas
• Tests and lint/format validations are passing
• My changes generate no new warnings

[ghost]

Code review. Looks reasonable!

[jonandernovella]

Except for the bug I mentioned, it looks good!

[jonandernovella]

Works great!