Get rid of useless move when assigning echRandom

Summary:
The `Random` is simply a std::array<unsigned char, 32>. `std::move(...)`
doesn't do anything special here other than a copy.

Remove the `std::move()` when assigning echRandom, as this confuses linters
into believing a use-after-move has taken place later on in
`constructEncryptedClientHello`.

Reviewed By: zxjtan

Differential Revision: D66211653

fbshipit-source-id: 0b0e4c2f96103ff5c698e9bdd915278ce35ab3a8

fizz/client/ClientProtocol.cpp

@@ -944,8 +944,7 @@ EventHandler<ClientTypes, StateEnum::Uninitialized, Event::Connect>::handle(
   folly::Optional<ClientPresharedKey> greasePsk;
 
   if (echParams.has_value()) {
-    // Swap out randoms first.
-    echRandom = std::move(random);
+    echRandom = random;
     context->getFactory()->makeRandomBytes(random.data(), random.size());
 
     // Generate GREASE PSK (if needed)