[Refactor] Enable auto-detection of screenshot generator renderer

[alvroble]

Description

Fixes #795. Changes made:

• Added is_screenshot_generator property to base Renderer class. Returns False by default
• Added is_screenshot_generator property to ScreenshotRenderer class. Returns True to identify it as the screenshot generator
• Removed the is_screenshot_renderer parameter from OpeningSplashView since it's no longer needed
• Modified OpeningSplashScreen to use self.renderer.is_screenshot_generator instead of the passed parameter
• Updated screenshot generator tests. Removed the is_screenshot_renderer parameter from the test configurations

This pull request is categorized as a:

• New feature
• Bug fix
• Code refactor
• Documentation
• Other

Checklist

• I’ve run pytest and made sure all unit tests pass before sumbitting the PR

If you modified or added functionality/workflow, did you add new unit tests?

• No, I’m a fool
• Yes
• N/A

I have tested this PR on the following platforms/os:

• Raspberry Pi OS Manual Build
• SeedSigner OS on a Pi0/Pi0W board
• Other

Note: Keep your changes limited in scope; if you uncover other issues or improvements along the way, ideally submit those as a separate PR. The more complicated the PR the harder to review, test, and merge.

[Chaitanya-Keyal]

tACK

[Chaitanya-Keyal]

I suggest rebasing with dev and modifying RestartView to also use renderer.is_screenshot_generator