stretchedmode: reduce wait time after changing scaling percentage

It now sets the max width and height right before the canvas is resized,
so the canvas size uses those max bounds immediately, instead of setting
it 500ms after the canvas is resized initially.

runescape-api/src/main/java/net/runelite/rs/api/RSGameEngine.java

@@ -51,4 +51,10 @@ public interface RSGameEngine extends GameEngine
 
 	@Import("replaceCanvasNextFrame")
 	void setReplaceCanvasNextFrame(boolean replace);
+
+	@Import("maxCanvasWidth")
+	void setMaxCanvasWidth(int width);
+
+	@Import("maxCanvasHeight")
+	void setMaxCanvasHeight(int height);
 }