Bugzilla

Steps to Reproduce:

- Open browser with sponsored tiles enabled
- Dismiss a sponsor tile or two
- restart the browser and open about:telemetry 
- search for newtab.blocked_sponsors
- verify that the value corresponds to the sponsor tiles' host name(?) that were dismissed previously

Steps to Reproduce:

- Open browser with sponsored tiles enabled
- Open a new tab and go to about:glean
- Under "About Testing" 2) select drop down to "New Tab"
- Click the "Apply settings and submit ping"
- Make note of the value in the textbox in point 1, go to https://debug-ping-preview.firebaseapp.com/ and find the entry
- Ensure a there is an existing payload has "newtab.blocked_sponsors" listed
- Go to the newtab page and dismiss one or two sponsored tiles
- Go back the about:glean page and click the button again
- Go to the debug-ping-preview page and see whether a new payload is produced with the "newtab.blocked_sponsors".