p4a command update

[WHG555]

When you run this command

buildozer android p4a clean_recipe_build pillow

This function takes as input ['p4a', 'clean_recipe_build', 'pillow']

def run_commands(self, args):

but can't run success.

[AndreMiras]

Thanks for the contribution.
This is covered with that syntax buildozer android p4a -- clean_recipe_build pillow, note the -- forwarding syntax.
Is this PR intended to add support for omitting the -- separator, or were you unaware of the existing syntax? If separator-free invocation is the intended enhancement, it needs to preserve the documented -- form and include tests for both forms.
I'm adding a test to make sure we won't introduce that regression in the future #2045