fix: exclude files in copy_to_directory before checking their realpath

[gregmagolan]

Allows for dangling symlinks inputs to be excluded before realpath is called on them.

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Test plan

• Covered by existing test cases

CI

[aspect-workflows]

Test

All tests were cache hits

215 tests (100.0%) were fully cached saving 44s.

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Test

e2e/copy_action

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

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Test

e2e/copy_to_directory

All tests were cache hits

6 tests (100.0%) were fully cached saving 583ms.

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Test

e2e/coreutils

All tests were cache hits

4 tests (100.0%) were fully cached saving 423ms.

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Test

e2e/external_copy_to_directory

All tests were cache hits

1 test (100.0%) was fully cached saving 73ms.

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Test

e2e/smoke

All tests were cache hits

6 tests (100.0%) were fully cached saving 2s.

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