Allow the host to send empty clipboards to the guest

the check was too strict.

Bug: 266956109
Test: check if clipboard sync host->guest
Change-Id: Id63612e8e7b5264af4def4e1f5ed5c1e25995b4c
Signed-off-by: Roman Kiryanov <rkir@google.com>

services/core/java/com/android/server/clipboard/EmulatorClipboardMonitor.java

@@ -111,7 +111,7 @@ class EmulatorClipboardMonitor implements Consumer<ClipData> {
         bb.order(ByteOrder.LITTLE_ENDIAN);
         final int msgLen = bb.getInt();
 
-        if (msgLen <= 0 || msgLen > MAX_CLIPBOARD_BYTES) {
+        if (msgLen < 0 || msgLen > MAX_CLIPBOARD_BYTES) {
             throw new ProtocolException("Clipboard message length: " + msgLen + " out of bounds.");
         }