vout_macosx: always set forced window size for the window provider
vout_macosx: always set forced window size for the window provider

Also fixes bug for retina displays where events got missed because
stored value is the pixel value, but new one is the point value.
(close #10743)

shyamalschandra/vlc,vlc-mirror/vlc,shyamalschandra/vlc,krichter722/vlc,krichter722/vlc,krichter722/vlc,krichter722/vlc,krichter722/vlc,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,shyamalschandra/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,krichter722/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,xkfz007/vlc,vlc-mirror/vlc,shyamalschandra/vlc,jomanmuk/vlc-2.2,xkfz007/vlc,shyamalschandra/vlc,vlc-mirror/vlc