Feature Request: When mapping controllers in Main, allow skipping analog X axis input and only assign Y.

[M-Walrus]

Currently when assigning analog sticks in the Main controller mapping screen, if you skip the X-axis for either stick, it will skip the Y-axis as well. This should be changed so that only the Y-axis can be assigned, for compatibility with many analog control devices that have a throttle.

This is important for devices like the Cyber Stick that only have a Y-axis for throttle, with an example given here by "T4YK" on Twitter:
https://twitter.com/T4YK_68000/status/1609960847660679168

With XE-1AP support now added, this would be needed if someone used a USB adapter for the original controller as well, as it only has Y-axis on the second stick: https://segaretro.org/XE-1_AP

This will also be helpful when XE-1AP support is added to other cores like Mega Drive, Sega CD, 32X, MSX and X68000.

[Koston-0xDEADBEEF]

I ran into the same issue, trying to get throttle working on a CH Fighterstick. It's possible to do it by hex editing the input map file directly, but you need to insert a bogus event number for the X axis - specifying only Y axis doesn't work.

00000060  00 00 02 00 01 00 02 00  03 00 02 00 02 00 02 00

Bytes at 0x68 and 0x6c are the joystick event numbers for X and Y axis.