Added 'safe apply' approach to avoid getting 'apply already in progress'...

... errors

I was seeing a "$apply already in progress error" on a page where I let the user upload documents. They can only upload one-at-a-time, and the error would happen on the SECOND upload.  I added this code which *seems* to get around it.  It's based on a "safe" apply approach that I found in a couple of posts.

I don't have a great way to test it, so it's tested minimally.  In other words, my page is working.  If you have a better idea of why this happens,  I'd be glad to hear it.