Return pip binary without -m flag when using onedir

[xeacott]

What does this PR do?

When using the onedir inside dist/run from pop-build, pip is provided and therefore cannot handle the -m flag. The pip module needs to handle this case.

What issues does this PR fix or reference?

Fixes:
https://github.com/saltstack/release-planning/issues/239

Previous Behavior

Remove this section if not relevant

New Behavior

Remove this section if not relevant

Merge requirements satisfied?

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[s0undt3ch]

Should we keep functionality as it was and provide an alternate logic if the app is frozen and/or has the sys._MEIPASS attribute?

[xeacott]

@s0undt3ch I'm open to taking this in a different direction. The heart of the issue is that the executable that sys.executable is reporting is not python, just something else; in the case of the onedir it's ./run. So the -m that gets passed around isn't going to a python binary but rather the pip binary.

[s0undt3ch]

Sure, and we should handle that. Draw your own conclusions and solution when running under pyinstaller.
If it's not running under pyinstaller, then the logic should remain as it is today.

Makes sense?

[s0undt3ch]

if under_pyinstaller:
     ...
else:
    ...