Client-side OpenGL support on Windows

[jzyrobert]

Describe the bug
When trying to use OpenGL on the Xpra client in Windows, some launched applications just show a white screen.
For example:
Doesn't work: Firefox, Xterm
Works: Chrome

To Reproduce
Steps to reproduce the behavior:

1. server command: xpra start
2. client command: xpra attach [host] --opengl=force
3. Launch xterm

System Information (please complete the following information):

• Server OS: Ubuntu 22
• Client OS: Windows 10
• Xpra Server Version: 4.4.5
• Xpra Client Version: 4.4.5

Additional context
The specific error encountered by OpenGL_check.exe is:

OpenGL errors:
  some required OpenGL functions are missing:
glActiveTexture, glMultiTexCoord2i

Searching the issues, this error is referenced in #640 but there's a lot of other tickets linked to it, I'm not sure if windows support was fixed and the error I'm seeing is due to missing opengl libraries, or because Xpra is not loading it properly.

[totaam]

My guess is that your MS Windows client OS is running in VirtualBox which lacks the OpenGL function that the client needs to enable OpenGL rendering.
Do not use --opengl=force and let it fallback to non-opengl rendering.