cp: apply umask to freshly created directories

[wtcpython]

Newly created directories previously inherited unmasked source permissions in recursive copy because copy_attributes promoted any freshly created directory to Preserve::Yes when mode was not explicitly disabled.

This applies the umask to freshly created directories when mode is not preserved, matching regular file copy behavior.

Fixes #14549.

[Copilot]

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[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/cut/bounded-memory (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)
Congrats! The gnu test tests/seq/seq-epipe is now passing!

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.