Fix RNN layers when strategy=resource

[vloncar]

Description

The RNN layers erroneously transposed layers during initialization in the backend, despite this functionality being moved into a separate pass. I also cleaned up the code a bit to align it more with the rest of the codebase. It fixes #779.

Type of change

• [x] Bug fix (non-breaking change that fixes an issue)

Tests

The existing test_rnn_accuracy has been extended to include strategy to verify the behavior is correct.

Test Configuration:

Checklist

• [x] I have read the guidelines for contributing.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have made corresponding changes to the documentation.
• [x] My changes generate no new warnings.
• [x] I have installed and run pre-commit on the files I edited or added.
• [x] I have added tests that prove my fix is effective or that my feature works.