pw_rpc: Use span copy constructor instead of iterator-based one

Change-Id: I09083a3d4f47aa7a7c6781710f26bb3d4a38e748
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/99287
Reviewed-by: Armando Montanez <amontanez@google.com>
Pigweed-Auto-Submit: Dennis Kormalev <denk@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>
diff --git a/pw_rpc/public/pw_rpc/internal/channel_list.h b/pw_rpc/public/pw_rpc/internal/channel_list.h
index c21224b..703fcaa 100644
--- a/pw_rpc/public/pw_rpc/internal/channel_list.h
+++ b/pw_rpc/public/pw_rpc/internal/channel_list.h
@@ -30,7 +30,7 @@
 class ChannelList {
  public:
   _PW_RPC_CONSTEXPR ChannelList(std::span<Channel> channels)
-      : channels_(channels.begin(), channels.end()) {}
+      : channels_(channels) {}
 
   // Returns the first channel with the matching ID or nullptr if none match.
   // Except for Channel::kUnassignedChannelId, there should be no duplicate