fix: use double instead of CGFloat for mjpegScalingFactor public API

[AsijitM]

Problem

FBConfiguration.h exposed CGFloat in its public interface:

+ (CGFloat)mjpegScalingFactor;
+ (void)setMjpegScalingFactor:(CGFloat)scalingFactor;

CGFloat is a CoreGraphics type, so the header depended on CoreGraphics even though it only imports
Foundation (it compiled only via a transitive Foundation → NSGeometry → CoreGraphics chain).

Fix (updated per review)

Rather than import CoreGraphics to prop up a CGFloat public API, switch the public getter/setter — and the
backing static — to double. CGFloat stays out of the public settings surface entirely, and the header
becomes self-contained with no CoreGraphics dependency.

+ (double)mjpegScalingFactor;
+ (void)setMjpegScalingFactor:(double)scalingFactor;

No behaviour change (CGFloat is double on 64-bit). Files: FBConfiguration.{h,m}.

[mykola-mokhnach]

I would rather prefer to explicitly use Double as type for settings. CGFloat is an internal implementation detail

[AsijitM]

Good call — updated. Instead of importing CoreGraphics, I switched mjpegScalingFactor/setMjpegScalingFactor: (and the backing static) to double, so CGFloat no longer leaks into the public settings API and the header no longer needs CoreGraphics. No behaviour change (CGFloat == double on 64-bit).