chmod: output permission denied error messages for inaccesible directories/files as regular user

[asder8215]

This PR modifies checking if a file exists from using .exists() to .try_exists() (handling it with match statements than if conditionals). This allows us to check for errors like PermissionDenied and output the error message accordingly for inaccesible directories/files as regular user. This fixes #9789.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/chmod/silent. tests/chmod/silent is passing on 'main'. Maybe you have to rebase?
GNU test failed: tests/chmod/thru-dangling. tests/chmod/thru-dangling is passing on 'main'. Maybe you have to rebase?

[asder8215]

I'm not sure if any of the errors on CICD/Build + L10n are the result of the changes I made to this code (it shouldn't affect anything because I just change the implementation of the code from using .exists() to .try_exists() and modified the error messages accordingly to match what GNU outputs). I see the same error for CICD/Build in #9796.

As for the WSL2 error, I ran the sync and df tests locally on my computer and it all passes. Can anyone else confirm anything about these errors?

[sylvestre]

sorry, it needs to be rebased

[asder8215]

@sylvestre, I just resetted the branch to the current updates that coreutils' main has and reapplied my changes within chmod.rs and test_chmod.rs