Improvements to the media uploader at responsive sizes:

* Change load order so larger breakpoint loads before smaller breakpoint.
* Use absolute positioning rather than floats, to fix some overflow issues.
* Remove the max-height media query so desktop browsers benefit from the responsive styles.
* Reset text inputs to 16px so iOS doesn't force zoom.
* Adjust the position of the close button so it doesn't overlap the Create Gallery link.

See #25977. Props joen.


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