Red-moon filter doesn't cover entire screen

[ghost]

Steps To Reproduce
turn on redmoon

Expected behavior:
S8 screen is something like an 18.5:9 aspect ratio -- redmoon used to, and should cover with the whole screen, but since 3.4.0 I think it stopped using the whole screen.

Actual behavior: [What actually happened.]
It does 16:9 when using newpipe, and something like 18:9 everywhere else. The redmoon filter partially covers the screen. See pictures.

Device info:

• Red Moon version (under Red Moon settings): [v3.5.0]
• Android version (under Settings > About device): [7.0]
• Device: [Samsung Galaxy S8]

[smichel17]

I have a Galaxy S5 also running 7.0 with no issues; it's interesting that this happens on an Android 7.0 device, otherwise I'd say it's likely a duplicate of #252 or the handful of similar issues.

If it was introduced in v3.4.0, it's probably a result of upgrading the target SDK (#260, context in #169). While it shouldn't have changed anything on devices below 8.0, that doesn't mean it didn't. So, the code for calculating dimensions probably needs a review.

My priorities recently have been places other than Red Moon*, so on the downside, I'm unlikely to work on this until/unless I get a new phone and run into similar issues. On the upside, filter size calculations are relatively self-contained (just 5 files), so it's a good jumping-in point for anyone who wants to try fixing this themselves, and (as noted in the README) I'm willing to help anyone who's interested.

*I plan to write a note about this soon to clarify my plans for maintenance going forward.