Splash screen when running from conda shows partially on Windows

[mrclary]

It seems that sphinx was not the only factor with the OP. pillow must also be installed for the splash screen to render properly. I don't understand this.

So installing Spyder from the installer, with sphinx < 7.4.0 and pillow included via matplotlib-base, there is no issue.

However, installing Spyder by itself, e.g. conda create -n test python=3.11 spyder=6.0.0.rc2, results in the bad splash screen.

The splash screen renders correctly:

• If the environment is activated first, e.g. conda run -n test spyder. Shortcuts do not activate the environment, as doing so creates a flashing cmd window. @jaimergp and I are unable to fix this.
• OR if the environment Library\bin is in the PATH environment variable. This is added to PATH when the environment is activated.
• OR if pillow is installed and sphinx < 7.4.0.

I suspect that Qt requires something in Library\bin and that the combination of sphinx < 7.4.0 and pillow either obviates the need for whatever is in Library\bin or alters Qt's search paths to include Library\bin.

Continuation of #22370

[mrclary]

Duplicate of #22374