Darker splash screen for system wide night mode

[sauravrao637]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

I think when using system wide dark mode, darker splash screen should be shown instead of the bright one.

Is your feature request related to a problem? Please describe it

"Oopps it's so bright even in darker mode" is what comes to mind every time I launch New Pipe :)

Additional context

as discussed in #6244

How will you/everyone benefit from this feature?

I know users using dark mode definitely want this.