Add option to allow @client directives to make it to the link chain

[jerelmiller]

This ticket is broken out of #10060 to track the work for points 1 and 2 in that issue:

1. Sending queries into the link chain with @client directives with an option to enable / disable by default.
2. Stripping those @client fields in HttpLink and other terminating links, if not handled earlier.

We can introduce this change in a non-breaking way by adding a new option that will allow the @client directives to make it to the link chain. The default value of this new option should maintain existing behavior which strips out @client before it makes it to the link chain. This will allow use cases where a developer might want to do some manipulation of the query with @client before it makes it to the terminating link.

Bonus: We might consider allowing individual queries to opt in/out of this behavior as well like we do with other options.

We'll need to update Documentation to explain this functionality as well.

[jerelmiller]

Finished with #10346