Fix URL encoding issue in pulp_file

[sbernhard]

closes #5686

Simiilar to https://github.com/pulp/pulp_deb/blob/b146fad9d894aeab89fe583a4fb60220a270744f/pulp_deb/app/tasks/synchronizing.py#L623 to quote the URL path.

[quba42]

I modified the change to not apply to file:// URLs (because this would break them).

Now all that is missing is a unit test. Although, to make it easy to write a unit test we probably need to split some of this out into a separate method. I don't think writing a unit test for the entire FileFirstStage.run() method is what we want.

[hstct]

Added unit tests rather than changing how the pytest fixture webserver serves the files which seems messy to begin with.

The test matrix is rather long but since the tests run very quickly I don't see the harm in being thorough :)

[quba42]

+1 to putting this in a helper method. I guess without it would have been pretty messy to unit test. 😆

[patchback]

Backport to 3.63: 💚 backport PR created

✅ Backport PR branch: patchback/backports/3.63/0d3b42171e305a4e9b8cb29b1cc1c4cd32ef93b8/pr-5835

Backported as #5991

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