This patch simply avoids calling SetAppID and SetCurrentProcessExplicitAppUserModelID when we're running from a packaged app. For `SetCurrentProcessExplicitAppUserModelID`, I ended up skipping the calls to the functions that call it because I thought it was less surprising behaviour given the names (eg: I might be surprised if `SetTaskbarGroupId` silently didn't set the taskbar group id). It's easy enough to switch up if skipping the calls at a lower level makes more sense.
I couldn't find any automated tests around the Jump List functionality (and we don't have any tests running within MSIX packages yet anyways...), but it worked just fine in my manual test. I also tested the scenario where the AppxManifest.xml ID changes during an upgrade (which will probably happen when https://bugzilla.mozilla.org/show_bug.cgi?id=1736113 gets done). This causes Jump Lists to stop working at first restart, but they appear to rebuilt after the usual few minute wait.
Differential Revision: https://phabricator.services.mozilla.com/D131693
c178143375