fixing commands fail when no folder

[memsharded]

Changelog: Fix: Avoid failures that happen when Conan runs in a non-existing folder.
Docs: Omit

Close #6075

It also includes some minor pep8 fixes in the command.py file

[memsharded]

I am moving this to draft. This responsibility is implemented already in the conan_api decorator, and in this point it wouldn't be necessary. The fix doesn't correct the error in the conan_api decorator.

[memsharded]

Moved responsibility to api, removed from main(). Please @jgsogo review again

[jgsogo]

Not a review, just a comment:

There are many places in Conan where we are calling os.getcwd or get_cwd (btw, why this file and comment?). This same cryptic error can be raised at any of those places.

Before this PR, Conan was failing at the very beginning, now Conan can fail with this exception at many different places. I'm not sure if it is better to raise a meaningful error than to protect/bypass at this point.

wdyt?

[memsharded]

Not a review, just a comment:

There are many places in Conan where we are calling os.getcwd or get_cwd (btw, why this file and comment?). This same cryptic error can be raised at any of those places.

Before this PR, Conan was failing at the very beginning, now Conan can fail with this exception at many different places. I'm not sure if it is better to raise a meaningful error than to protect/bypass at this point.

wdyt?

I have checked the code, in practice, many commands that do not require the current path (search, remove, upload), do not use getcwd at all, so I think this would be already an improvement for those commands.

For other commands, yes the error will be equally cryptic, and raised at different places. We could wrap in the get_cwd (was initially intended for unicode) for every os.getcwd() in the codebase (or at least in the first call of relevant commands), to protect against this error. Probably not worth, just a small UX improvement for a not critical thing.

[jgsogo]

Ok