Remove top-level const from parameters in function declarations.

This is a safe cleanup change since top-level const applied to
parameters in function declarations (that are not also
definitions) are ignored by the compiler. Hence, such changes do
not change the type of the declared functions and are simply
no-ops.

Bug: webrtc:13610
Change-Id: Ibafb92c45119a6d8bdb6f9109aa8dad6385163a9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/249086
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Ali Tofigh <alito@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35802}

rtc_base/experiments/struct_parameters_parser.h

@@ -28,7 +28,7 @@ namespace webrtc {
 namespace struct_parser_impl {
 struct TypedMemberParser {
  public:
-  bool (*parse)(const absl::string_view src, void* target);
+  bool (*parse)(absl::string_view src, void* target);
   void (*encode)(const void* src, std::string* target);
 };