Only interesting FTV1 traces should be sent

[BrynCooke]

FTV1 traces are heavy, and we should therefore only send them if they look interesting. They are already filtered on the server side, but it is a wast of bandwidth to send them in the first place if they are not interesting.

More info here: https://github.com/apollographql/router/pull/1514#issuecomment-1226415941