GoogleVideoSearch: fix blank description; invalid thumbnails
GoogleVideoSearch: fix blank description; invalid thumbnails

## Issue
Closes 5923 video metadata issues

## Notes
For thumbnails, future claims should have correct thumbnails after `5925 Fix thumbnail-checking and block 'data:image'`. For existing claims, we'll just skip the metadata to avoid the crawler error. Users can easily update their thumbnails.

For the `OlivOliv` thumbnail url case, I wasn't sure whether to go all out to fetch and verify each thumbnail. I ended up just checking whether it starts with `http(s)`

lbryio/lbry-app,lbryio/lbry-app