Log Message:
thunderbird: Update to 68.4.1

Changelog:
Changes
Various improvements when setting up an account for a Microsoft Exchange server: \ 
Now offers IMAP/SMTP if available, better detection for Office 365 accounts; \ 
re-run configuration after password change.

Fixes
Attachments with one or more spaces in their names couldn't be opened under some \ 
circumstances

After changing view layout, the message display pane showed garbled content \ 
under some circumstances

Tags were lost on messages in shared IMAP folders under some circumstances

Various theme changes to achieve "pixel perfection": Unread icon, \ 
"no results" icon, paragraph format and font selector, background of \ 
folder summary tooltip

Calendar: Event attendee dialog was not displayed correctly

Various security fixes

Security fixes:
CVE-2019-17026: IonMonkey type confusion with StoreElementHole and \ 
FallibleStoreElement
#CVE-2019-17015: Memory corruption in parent process during new content process \ 
initialization on Windows
#CVE-2019-17016: Bypass of @namespace CSS sanitization during pasting
#CVE-2019-17017: Type Confusion in XPCVariant.cpp
#CVE-2019-17021: Heap address disclosure in parent process during content \ 
process initialization on Windows
#CVE-2019-17022: CSS sanitization does not escape HTML tags
#CVE-2019-17024: Memory safety bugs fixed in Thunderbird 68.4.1