Revert pen input flow and map pen to touch on mobile platforms

[frenzibyte]

• Alternative to / closes Fix pen input not being friendly with touch #6509
• Alternative to Enable mouse/pen aim + touch click play style osu#31704
• Closes Cannot play osu! with pen + touch input osu#31570

After multiple attempts to try and fix ppy/osu#31570, this is one which brings back osu! to how it has been working before.

Now since direct/onscreen pen input is mapped to touch input, the entire pen input / ISourcedFromPen API becomes flaky and inconsistent, as not all pen input are sent as an ISourcedFromPen mouse event. For simplicity purposes, I have chosen to revert it completely until later time.

When returning back to resurrect this flow, special attention needs to be given into the following intertwined two problems:

• PassThroughInputManager.syncReleasedInputs() should respect mouse input sourced from pen (currently sends release input without such context)
• PassThroughInputManager.syncReleasedInputs() should be aware whether mouse button pressed from parent comes from mouse and not other input sources (main reason why it's impossible to make this flow work with OsuTouchInputMapper)