[rcore] fix gamepad axis movement and its automation event recording (#4184)
* [rcore] fix gamepad axis movement and its automation event recording
This commit fixes 2 issues:
- Automation events aren't recorded for negative axis movements on
gamepads (e.g. stick going left/up)
- 'GetGamepadAxisMovement' drift check isn't working correctly for
triggers. Axis values between [-0.1, 0.1] are clamped to 0.0
Behaviour change:
- 'GetGamepadAxisMovement' returns default value for each axis, even
if gamepad isn't attached.
* [rcore] inline body of 'GetGamepadAxisMovementDefault' and remove it