[Orbit] Add missing type hints to utility and runner modules

[LINYV0719]

Description

This PR adds missing type hints to orbit/utils, orbit/actions, and orbit/standard_runner.py to improve code readability, IDE autocompletion support, and static analysis.

Files of changes: orbit/utils/epoch_helper.py orbit/utils/common.py orbit/actions/export_saved_model.py orbit/standard_runner.py orbit/utils/loop_fns.py

Type of change

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Note: Please delete options that are not relevant.

• [x] Documentation update
• [x] Other (Code health)

Tests

I verified the changes by running the existing unit tests for the modified modules to ensure no functionality was broken and no syntax errors were introduced.

Test Configuration:

OS: Windows Python Version: Python 3.10 Commands ran: python -m orbit.utils.common_test python -m orbit.actions.export_saved_model_test python -m orbit.standard_runner_test

Checklist

• [x] I have signed the Contributor License Agreement.
• [x] I have read guidelines for pull request.
• [x] My code follows the coding guidelines.
• [x] I have performed a self code review of my own code.
• [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 added tests that prove my fix is effective or that my feature works.