MuseScore 3.5.2 Release. PRs to be merged and issues to be fixed.

[Jojo-Schmitz]

• Fix issue with en_US translation getting fed back into Transifex #6322 - Fix issue with en_US translation getting fed back into Transifex (needed before translations get enabled again, so latest in 3.6!)
• add extended fermata symbols to MusicXML I/O #6560 - Add extended fermata symbols to MusicXML I/O (not really a regression, therefor might get postponed to 3.6)
• Fixed unexpected geometry stretching in "Edit style" dialog #6651 - Fixed unexpected geometry stretching in "Edit style" dialog
• fix #311520: harmony playback preferences not honored until toggled #6653 - Fix #311520: Harmony playback preferences not honored until toggled
• [MU3] fix #311621: fixed export audio on Windows #6665 - Fix #311621: Fix export audio on Windows
• Fix #311661: Fix potential crash in PianoView::updateNotes() #6667 - Fix #311661: Fix potential crash in PianoView::updateNotes() (not really a regression though)
• Fix #311796: Crash when deleting header/footer text after hiding #6681 - Fix #311796: Crash when deleting header/footer text after hiding (3.5(.0) regression, therefor might get postponed to 3.6?)

3.5.1 Regressions with no PR or fix yet:

• Fix #311516: False or old link when downloading the latest version 3.5.1 (website issue)
• Fix #311526: Automatic downloading failed for Windows portable version (website issue)
• Fix #311695: Edits to system text/tempo marking after save and reload of score do not propagate to all parts. (fixed by reverting an earlier PR)
• Fix #311748: Updated translations don't show in MuseScore

3.5(.0) Regressions with no PR yet:

• Fix #306644: Preferences window doesn't match on a 15'' Laptop screen and height isn't resizeable @Spire42 ?
• Fix #308726: Voice 1 rests collide with voice 3 rhythm slashes (above the staff)
• Fix #308925: User velocity does nothing
• Fix #308975: Display and editing of lines is wrong @RomanPudashkin
• Fix #309040: Rest auto avoidance flawed @tobik ?
• Fix #309102: Dragging handle of hairpin (or other line) causes it to shoot off in the other direction
• Fix #309188: Doesn’t merge rests into one when the measure has 3 or 4 voices. @tobik ?
• Fix #309368: Lines: when end handles are adjusted with keyboard arrows, anchor point also shifts

Other long-time and frequent issues (where the real cause still is very unclear):

• Very many issues and forum posts of 'no sound', where sometimes How to restore sound if playback stops working, but quite often not
• Fix #271185: Scores corrupted beyond repair, containing nothing but zeros