Add device clipboard set acknowledgement

Add a device message type so that the device could send acknowledgements
for SET_CLIPBOARD requests.

PR #2814 <https://github.com/Genymobile/scrcpy/pull/2814>

app/src/device_msg.c

@@ -1,5 +1,6 @@
 #include "device_msg.h"
 
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -34,6 +35,11 @@ device_msg_deserialize(const unsigned char *buf, size_t len,
             msg->clipboard.text = text;
             return 5 + clipboard_len;
         }
+        case DEVICE_MSG_TYPE_ACK_CLIPBOARD: {
+            uint64_t sequence = buffer_read64be(&buf[1]);
+            msg->ack_clipboard.sequence = sequence;
+            return 9;
+        }
         default:
             LOGW("Unknown device message type: %d", (int) msg->type);
             return -1; // error, we cannot recover