Bug 1004329 - [Flatfish][Homescreen] Returning home (landscape) from portrait app causes app icons to misalign/overlap

* Remove the window.matchMedia event handler which updates the width and height cache every time the orientation is changed to portrait.
Merge pull request #23657 from begeeben/1004329_returning_home

Bug 1004329 - [Flatfish][Homescreen] Returning home (landscape) from portrait app causes app icons to misalign/overlap, r=:crdlc