DolphinQt/InputCommon: Make input mapping and output testing non-blocking.

[jordan-woyak]

Normal Mapping Window:
Multiple input mappings can be queued/un-queued/cleared without the UI blocking.
This allows for quicker batch input mapping for power users.
Mapping a mouse-click itself requires clicking not on a mapping button.
Each mapping button interaction resets the timeout.
Waiting for the timeout cancels all queued input mappings.
Interacting with the window in other ways cancels in-progress mappings appropriately.

simplescreenrecorder-2024-11-02_00.55.44.mp4

"Advanced" Window:
The live previews now update while detecting inputs.
Button labels are renamed to be more clear.

simplescreenrecorder-2024-11-02_00.59.57.mp4

Output/Rumble test in the "Advanced" window is also now non-blocking.
Clicking it while active will stop the rumble test.

Overall, mapping window interaction is less terrible when input detection is non-blocking.

[dreamsyntax]

I have not reviewed the code, but I did some testing on this branch.
This does not resolve the input dropping/locking that occurs for rapidly setting buttons unfortunately, but it does fix the Window Focus() constant re-calling and general bad feeling of the Input Window.

Great job with this!

[JosJuice]

Can't say I reviewed every single line in detail, but this looks reasonable. Some minor comments.

[dreamsyntax]

Tested latest commit on both Windows and Linux (Flatpak).
Tested SDL backend for controllers, and keyboard on both linux/windows.
Works great.
Code LGTM too.