Revert "Fix PL docs build on readthedocs.org (#15511)"

[akihironitta]

This reverts commit e818e82.

What does this PR do?

Reverts the commit since it didn't work and the issue was resolved by #15493.

Does your PR introduce any breaking changes? If yes, please list them.

None

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cc @Borda @carmocca @akihironitta