RPC: increase max message size (#2543)

* RPC: increase max message size
* RPC: do not use magic numbers

applications/services/rpc/rpc.c

@@ -244,7 +244,7 @@ static int32_t rpc_session_worker(void* context) {
             .callback = rpc_pb_stream_read,
             .state = session,
             .errmsg = NULL,
-            .bytes_left = RPC_MAX_MESSAGE_SIZE, /* max incoming message size */
+            .bytes_left = SIZE_MAX,
         };
 
         bool message_decode_failed = false;

applications/services/rpc/rpc.h

@@ -10,7 +10,6 @@ extern "C" {
 #endif
 
 #define RPC_BUFFER_SIZE (1024)
-#define RPC_MAX_MESSAGE_SIZE (1536)
 
 #define RECORD_RPC "rpc"