internal/ui: maximizing window via button is still available when window's max size is determined

[erexo]

In #2259 there was an attempt to fix flickering size-dependent window during maximization, but given case can still be achieved by clicking on the "Maximize" button on the window frame.

[hajimehoshi]

Same as linux.

[hajimehoshi]

I think this is an issue in GLFW

[hajimehoshi]

glfw/glfw#1103 (comment)