fix(RemoteFile): Don't try to delete unavailable S3 file

[cogk]

If I'm not mistaken, unavailable Remote Files could be removed (like other Log Types) once they become unavailable.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 29.94%. Comparing base (2f435f8) to head (b6b667a).

Files with missing lines	Patch %	Lines
press/press/doctype/remote_file/remote_file.py	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2259 +/- ## ========================================== - Coverage 29.94% 29.94% -0.01% ========================================== Files 371 371 Lines 28078 28079 +1 ========================================== Hits 8408 8408 - Misses 19670 19671 +1 ```

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