Drop the "Onion Logo" from trademark statement

Currently, in the "About Tor Browser" dialog, we have the statement:

“Tor” and “The Onion Logo” are registered trademarks of The Tor Project, Inc.

We don't actually use the trademarked onion logo in our builds any more. See the trademark here: https://tsdr.uspto.gov/#caseNumber=77172363&caseSearchType=US_APPLICATION&caseType=DEFAULT&searchType=statusSearch

I've searched through our assets and I can't find this old logo, which I think was cleared out with the new designs from UX. @donuts can you please confirm we won't use the logo any more?

So I think we should change it to:

`“Tor” is a registered trademark of The Tor Project, Inc.