Introcuce RTCError(const T&) constructor.

This CL is spawned from [1] and it introduces RTCError(const T&) in
order to remove an unneeded std::move.

[1] - https://webrtc-review.googlesource.com/c/src/+/120350

Bug: webrtc:10252
Change-Id: Ibd5aa1c901fd920549e9437908178c786019a328
Reviewed-on: https://webrtc-review.googlesource.com/c/120560
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26468}
diff --git a/api/rtc_error.h b/api/rtc_error.h
index 673a79a..904a619 100644
--- a/api/rtc_error.h
+++ b/api/rtc_error.h
@@ -220,6 +220,7 @@
   // NOTE: Not explicit - we want to use RTCErrorOr<T> as a return type
   // so it is convenient and sensible to be able to do 'return T()'
   // when the return type is RTCErrorOr<T>.
+  RTCErrorOr(const T& value) : value_(value) {}        // NOLINT
   RTCErrorOr(T&& value) : value_(std::move(value)) {}  // NOLINT
 
   // Delete the copy constructor and assignment operator; there aren't any use