Add Mend reachability analysis

[jackdawm]

What was changed

This is the json snippet support gave me, but I added the gradle ignore we had before.

Why?

"Reachability analysis" should make the Mend dependency alerts less noisy by seeing when we aren't using the vulnerable component of the problematic library.

Checklist

How was this tested:

I'm hoping I can test this scanning change while this is a PR. I'll update this later with whatever I figure out.