DesktopHOC manages project title, rather than wrapping with TitledHOC

[benjiwheeler]

scratchfoundation/scratch-gui#5168 proposed a refactor where TitledHOC changed its role from:
Before: "wrap GUI and maintain projectTitle state, if no other external parent is maintaining it"
to
After: "wrap GUI and interface between external parent's projectTitle prop, and GUI's redux projectTitle"

This means that TitledHOC can't be used to wrap ScratchDesktopHOC anymore -- it no longer does the thing we used it for. Instead, ScratchDesktopHOC needs to maintain its own projectTitle state, since the main Electron process may send a projectTitle in on file load.

Important: this should only be merged if scratchfoundation/scratch-gui#5168 is also merged. scratchfoundation/scratch-gui#5168 should be merged first, so the resulting version of GUI can be used by scratch-desktop.

[benjiwheeler]

I labeled this "needs discussion" because it's not 100% clear yet that this is the direction we're going to go in GUI.

[cwillisf]

LGTM, pending scratchfoundation/scratch-gui#5168 of course :)

[benjiwheeler]

@cwillisf I think we're ready to merge this -- could you test it to confirm that it works, before I do?

[benjiwheeler]

@cwillisf wrote:

"I tried it out and ran into two issues. One is an easy fix: in app.jsx, WrappedComponent needs canEditTitle so the title box shows up. The other issue is maybe a little stranger... I don't immediately see what's going wrong, but the setTitleFromSave stuff isn't currently working. That is, changing the project file name in the save dialog doesn't cause the title box to update."

[benjiwheeler]

Next step: get desktop running locally, so I can debug this PR

[benjiwheeler]

OK @cwillisf, please try it out now! It should be working:

[cwillisf]

Looks good! I tested it locally and everything seemed to be in working order. Thanks!