fix CI errors from FlxPool changes

[Geokureli]

Fixes issues on -Dcoverage1:

/home/runner/haxe/haxelib/flixel/git/flixel/math/FlxRect.hx:25: characters 20-23 : { putUnsafe : flixel.math.FlxRect -> Void } has no field get
/home/runner/haxe/haxelib/flixel/git/flixel/math/FlxRect.hx:27: characters 3-14 : flixel.math.FlxRect should be { _inPool : Bool }
/home/runner/haxe/haxelib/flixel/git/flixel/math/FlxRect.hx:27: characters 3-14 : ... The field _inPool is not public
/home/runner/haxe/haxelib/flixel/git/flixel/math/FlxRect.hx:518: characters 3-15 : { putUnsafe : flixel.math.FlxRect -> Void } should be flixel.util.IFlxPool<flixel.math.FlxRect>

Note that i haven't been able to reproduce coverage2 issues:

/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:174: characters 28-32 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field keys
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:174: characters 16-34 : You can't iterate on a Dynamic value, please specify Iterator or Iterable
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:112: characters 16-38 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field iterator
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:230: characters 16-19 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:249: characters 16-22 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field remove
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:307: characters 17-20 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:360: characters 17-20 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:416: characters 17-20 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:496: characters 17-20 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:836: characters 17-28 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field iterator
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:853: characters 29-33 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field keys
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:853: characters 17-35 : You can't iterate on a Dynamic value, please specify Iterator or Iterable
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:868: characters 22-28 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field exists
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:885: characters 15-18 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field set (Suggestion: get)
/home/runner/haxe/haxelib/flixel/git/flixel/animation/FlxAnimationController.hx:887: characters 15-21 : { get : String -> Null<flixel.animation.FlxAnimation> } has no field remove

gonna mess with those in another PR