[mojo][bindings] Remove redundant deserialization error description

Since ReportValidationError() already logs the description from its
|context| parameter, there is no need to pass the description separately.

Test: temporarily triggered the deserialization error and confirmed the error message has only one instance of interface name and method number

Change-Id: I813052bbaf4485d1fd269174b3a645535f548c7c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2157721
Commit-Queue: Oksana Zhuravlova <oksamyt@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#761122}

mojo/public/cpp/bindings/lib/validation_errors.cc

@@ -104,7 +104,7 @@ void ReportValidationErrorForMessage(mojo::Message* message,
                          is_response ? " response" : "");
   ValidationContext validation_context(nullptr, 0, 0, 0, message,
                                        description.c_str());
-  ReportValidationError(&validation_context, error, description.c_str());
+  ReportValidationError(&validation_context, error);
 }
 
 ScopedSuppressValidationErrorLoggingForTests