onGameResize called every time an overlay is added and when game starts

[dbilgin]

Current bug behaviour

Whenever a game starts for the first time or whenever gameRef.overlays.add is called after for example a level is done, onGameResize is called.

Expected behaviour

For the game start, I think this shouldn't be called as the game is not "resized" but just created for the first time and adding an overlay should simply not trigger a game resize.

Steps to reproduce

• Create a game
• Add an overlay after the game is launched

Environment information

• Flame version: ^1.2.0
• Platform affected: android, ios, web
• Platform version affected: seems to be all
• Flutter (Channel stable, 3.0.4, on macOS 12.2.1 21D62 darwin-arm, locale en-DE)