Log Message:
thunderbird: Update to 115.5.1

* Use ffmpeg6.

Changelog:
Fixes

fixed
Advanced GnuPG keys may be protected with an unexpected passphrase

fixed
OpenPGP signatures rejected due to mismatched signature timestamp now display
signature timestamp and clarifying message

fixed
Advanced address book search did not return results if display name was left
blank

fixed
Clicking on attendee when inviting attendees added the attendee twice