Make entering a rest switch to input mode

Resolves: #24282

Entering a rest with the keyboard shortcut now automatically enters input mode and advances to the next note. This is arguably the expected behaviour, since inputing a note switches to input mode.

[x] I signed the CLA
[x] The title of the PR describes the problem it addresses
[x] Each commit's message describes its purpose and effects, and references the issue it resolves
[x] If changes are extensive, there is a sequence of easily reviewable commits
[x] The code in the PR follows the coding rules
[x] There are no unnecessary changes
[x] The code compiles and runs on my machine, preferably after each commit individually
[x] I created a unit test or vtest to verify the changes I made (if applicable)

musescore / MuseScore

Make entering a rest switch to input mode #24995