Swap sending of SETTINGS ACK frame and emitting the signal

This allows API users sending the HEADERS and DATA frames after the
SETTINGS ACK right from settingsFrameReceived slot, and keep the
expected frame order.

Pick-to: 6.8 6.9
Change-Id: I7900e786074d1d534c2e14f00e2aedf8dbb3a9d9
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/network/access/qhttp2connection.cpp

@@ -1602,8 +1602,8 @@ void QHttp2Connection::handleSETTINGS()
     }
 
     qCDebug(qHttp2ConnectionLog, "[%p] Sending SETTINGS ACK", this);
-    emit settingsFrameReceived();
     sendSETTINGS_ACK();
+    emit settingsFrameReceived();
 }
 
 void QHttp2Connection::handlePUSH_PROMISE()