Custom report sources selection is not ordered consistently

To test this, we'll change the language string used by one of the report sources (lang/en/badges.php):

1. Edit the 'badges' string in the aforementioned file to 'ZZ Badges', e.g. this diff:

   -$string['badges'] = 'Badges';

   +$string['badges'] = 'ZZ Badges';

2. Purge lang string caches
3. Navigate to Reports from user menu
4. Press New report
5. Enter a name
6. Expand the Report source select element
7. Confirm the sources are listed alphabetically (ZZ Badges should be last)
8. Select the ZZ Badges report source
9. Press Save
10. Confirm a new report is created from the badges report source