Fix handling of VectorDrawable in icon requests

[moertel]

This commit changes the way unthemed icons (for display in the icon requests section) are loaded by Glide. Where it would previously load by package name (presumably using a custom resource but I didn't find it), it's now getting the drawable directly. This fixes VectorDrawables going unhandled and showing up as blank.

Similarly, getRightIcon returning null would cause the user to get stuck on the Building request... dialog when they would try to submit an icon request containing a VectorDrawable. This is a problem in and of itself (e.g. if new drawable types come up) but I chose to go the way of least resistance and simply add a handler for VectorDrawable specifically.

Fixes #119

[moertel]

Still a draft while I test the fix in Prod :)

[moertel]

I can confirm that E-Mail icon requests for VectorDrawables are working 💪