Remove path to Python in .bat files

[gillins]

Checklist

• [x] Used a fork of the feedstock to propose changes
• [x] Bumped the build number (if the version is unchanged)
• [x] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [x] Ensured the license file is being packaged.

xref: https://github.com/conda-forge/qgis-feedstock/pull/86

63 didn't fix the issue of the build path being embedded in the .bat files. This is another attempt and it simply removes the path from the Python command so it can be found in any environment. Any better suggestions of how to fix Windows properly greatly received!

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[gillins]

@conda-forge-admin, please rerender

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-webservice.

I tried to re-render for you but ran into some issues, please ping conda-forge/core for further assistance.

[ocefpaf]

Thanks @gillins!