Fix useless move() in //c/credential_provider/gaiacp/

Drop std::move() call that has no effect and only triggers the
"bugprone-use-after-move" clang-tidy warning.

Bug: 1122844
Change-Id: Icf792dbe102e61976e7f86454d2bdc8fcf369979
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560269
Commit-Queue: Yusuf Sengul <yusufsn@google.com>
Auto-Submit: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Yusuf Sengul <yusufsn@google.com>
Cr-Commit-Position: refs/heads/master@{#831092}

chrome/credential_provider/gaiacp/gem_device_details_manager_unittests.cc

@@ -62,8 +62,7 @@ TEST_P(GemDeviceDetailsExtensionTest, WithUserDeviceContext) {
   }
 
   base::Value expected_response_value(base::Value::Type::DICTIONARY);
-  expected_response_value.SetStringKey("deviceResourceId",
-                                       std::move(device_resource_id));
+  expected_response_value.SetStringKey("deviceResourceId", device_resource_id);
   std::string expected_response;
   base::JSONWriter::Write(expected_response_value, &expected_response);