Windows: no rumble with Switch Pro Controller

First and foremost consider this:

• Only RetroArch bugs should be filed here. Not core bugs or game bugs
• This is not a forum or a help section, this is strictly developer oriented

Description

The Switch Pro Controller fails to rumble in Windows (RetroArch log console reports [WARN] [SDL]: Couldn't open haptic device of the joypad #0: Haptic: There are 0 haptic devices available)

Expected behavior

I expect the controller to rumble when appropriate, as it does in, for example, mGBA standalone.

Actual behavior

The controller isn't even identified as capable of rumble.

Steps to reproduce the bug

1. Sync Switch Pro Controller to Windows
2. Launch RetroArch from command line with -v
3. Change controller driver to sdl2 and restart RetroArch
4. Observe above-mentioned warning

Bisect Results

[Try to bisect and tell us when this started happening]

Version/Commit

You can find this information under Information/System Information

• RetroArch: 1.10.3/d0ef0ec

Environment information

• OS: Windows 10 Home x64
• Compiler: MinGW (10.2.0) 64-bit

Start by examining RetroArch's SDL2 controller and haptic handling, using the verbose launch steps with a Switch Pro Controller on Windows 10. Confirm the warning about zero haptic devices and compare behavior with the sdl2 driver. Done means the controller is recognized as rumble-capable and rumbles when appropriate.