[web] Move exifRotate from input-state-container to media-utils

Summary:
I needed to use validateFile outside of input-state-container, but saw that it took exifRotate as an argument.

I first considered moving exifRotate to media-utils and exporting it globally so I could access it from input-state-container and elsewhere. But upon reading the code further, it looks like we only ever use exifRotate in processFile(file: File), so I just moved it right above without exporting.

Depends on D8363 (kind of)

Test Plan:
Logged value of browser and exifRotate in Safari/Chrome/FireFox:

Reviewers: ashoat, ginsu, rohan

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8364