fix packet queue full (#6292)

src/mesh/api/PacketAPI.cpp

@@ -89,6 +89,7 @@ bool PacketAPI::receivePacket(void)
 
 bool PacketAPI::sendPacket(void)
 {
+    if (server->available()) {
         // fill dummy buffer; we don't use it, we directly send the fromRadio structure
         uint32_t len = getFromRadio(txBuf);
         if (len != 0) {
@@ -99,7 +100,8 @@ bool PacketAPI::sendPacket(void)
                 LOG_ERROR("send queue full");
             }
             return result;
-    } else
+        }
+    }
     return false;
 }