feature: simplify the setup (tests + dev = dev)

[GreatBahram]

Description

The tests and dev extras were nearly identical, with only minor differences. To reduce redundancy and simplify the setup process for contributors, I've merged the tests dependencies into the dev group and removed the tests extra entirely.

Let me know if you'd prefer to keep them separate for any reason.

Related Issue

Fixes #(issue number)

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

[GreatBahram]

[johannaSommer]

LTGM, thanks for the cleanup @GreatBahram

[johnrachwan123]

LGTM! Thanks :)