This update for MozillaThunderbird fixes the following issues:

- Mozilla Thunderbird was updated to 78.7.0 ESR (MFSA 2021-05, bsc#1181414)
* CVE-2021-23953: Fixed a Cross-origin information leakage via redirected PDF requests
* CVE-2021-23954: Fixed a type confusion when using logical assignment operators in JavaScript switch statements
* CVE-2020-26976: Fixed an issue where HTTPS pages could have been intercepted by a registered service worker when they should not have been
* CVE-2021-23960: Fixed a use-after-poison for incorrectly redeclared JavaScript variables during GC
* CVE-2021-23964: Fixed Memory safety bugs
* CVE-2020-15685: Fixed an IMAP Response Injection when using STARTTLS

This update was imported from the SUSE:SLE-15:Update update project.