Remove usage of std::move usage for std::string_views

* Michael pointed out in https://skia-review.googlesource.com/c/skia/+/1089276/comments/db266ec1_838cfddc that using std::move on string_views doesn't really offer any benefit. While it should be a no-op, removing it will cut down on confusion / redundancy.

Change-Id: I019b8d598dbfbbce8d1e5a64c8ebe289362e83a6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/1142776
Auto-Submit: Nicolette Prevost <nicolettep@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Thomas Smith <thomsmit@google.com>
Commit-Queue: Nicolette Prevost <nicolettep@google.com>