cli: fix parsing for scripts

[Borda]

Before submitting

• Was this discussed/agreed via a Github issue? (no need for typos and docs improvements)
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• Did you make sure to update the docs?
• Did all existing and newly added tests pass locally?

What does this PR do?

Addressing #371 (comment)

PR review

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📚 Documentation preview 📚: https://lit-utilities--419.org.readthedocs.build/en/419/

[Copilot]

Pull Request Overview

This PR fixes argument parsing behavior in CLI scripts by updating jsonargparse usage. The changes standardize how optional arguments are handled across multiple scripts, ensuring they are parsed as optional parameters rather than positional ones.

Key changes:

• Updates auto_cli calls to use as_positional=False parameter
• Adds comprehensive test coverage for different argument parsing scenarios
• Affects three script files that use jsonargparse for CLI parsing

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/scripts/test_adjust_torch_versions.py	Adds parametrized test to verify positional, optional, and mixed argument parsing
scripts/inject-selector-script.py	Updates auto_cli call to disable positional argument parsing
scripts/adjust-torch-versions.py	Updates auto_cli call to disable positional argument parsing
.github/scripts/find-unused-caches.py	Updates auto_cli call to disable positional argument parsing

Comments suppressed due to low confidence (1)

tests/scripts/test_adjust_torch_versions.py:41

• [nitpick] The variable name main_params is ambiguous. Consider renaming it to script_parameters or cli_parameters to better indicate its purpose.

    main_params = (("requirements_path", path_req_file), ("torch_version", "1.10.0"))