Remove rsocket payload size assertion

Summary:
Don't fatal when trying to send a message to flipper that is too large.
Instead just continue to throw an exception, so the plugin will still be aware of the failure.

Reviewed By: cpojer, danielbuechele

Differential Revision: D17180334

fbshipit-source-id: 49c341a7cee579158be3878639083c6d19b3eaa3

xplat/Flipper/FlipperConnectionManagerImpl.cpp

@@ -356,7 +356,6 @@ rsocket::Payload toRSocketPayload(dynamic data) {
             "Error: Skipping sending message larger than max rsocket payload: ") +
         json.substr(0, 100) + "...";
     log(logMessage);
-    DCHECK_LE(payloadLength, maxPayloadSize);
     throw std::length_error(logMessage);
   }