[Wildcard Variables] support for `avoid_final_parameters`

[pq]

From the rule description:

Declaring parameters as final can lead to unnecessarily verbose code, especially when using the "parameter_assignments" rule.

My sense is we don't want to special case wildcards and flag final wildcards just like any other wildcard.

/cc @kallentu @bwilkerson @lrhn

[pq]

Tested w/ 964017a