Bug 25922: Add aria-label to the allowlist for translation

Bug 25922: Add aria-label to the allowlist for translation

This patch adds aria-label to the allowlist for translations.

To test:
- Apply patches from here and bug 25244
- kshell
- cd misc/translator
- perl translate update de-DE
- Check for the aria-label in the diff
- Verify the strings appear in the po files now
- Translate them
- perl translate install de-DE
- Verify the translated strings appear in the template

Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>