Don't load beta features code on mobile

hehe.
If you do then Special:Nearby refresh icon breaks.
Also certain styles are loaded twice.
We shouldn't do this. Luckily this should only effect
a small minority of our audience.

Change-Id: Icd1cd6e6e526068c93879e7bcffbc59d8c11aebd
Merge "Don't load beta features code on mobile"