Fix remote mouse: you can drag but not drop in Plasma Wayland

plugins/mousepad/mousepadplugin.cpp

@@ -66,6 +66,7 @@ void MousepadPlugin::connected()
     if (m_impl) {
         np.set<bool>(QStringLiteral("state"), m_impl->hasKeyboardSupport());
     }
+    np.set<bool>(QStringLiteral("singlerelease_support"), true);
     sendPacket(np);
 }
 

plugins/mousepad/waylandremoteinput.cpp

@@ -240,7 +240,6 @@ bool WaylandRemoteInput::handlePacket(const NetworkPacket &np)
             // For drag'n drop
             s_session->iface->NotifyPointerButton(s_session->m_xdpPath, {}, BTN_LEFT, 1);
         } else if (isSingleRelease) {
-            // For drag'n drop. NEVER USED (release is done by tapping, which actually triggers a isSingleClick). Kept here for future-proofness.
             s_session->iface->NotifyPointerButton(s_session->m_xdpPath, {}, BTN_LEFT, 0);
         } else if (isScroll) {
             s_session->iface->NotifyPointerAxis(s_session->m_xdpPath, {}, dx, dy);

plugins/mousepad/x11remoteinput.cpp

@@ -131,7 +131,6 @@ bool X11RemoteInput::handlePacket(const NetworkPacket &np)
             // For drag'n drop
             XTestFakeButtonEvent(display, mainMouseButton, True, 0);
         } else if (isSingleRelease) {
-            // For drag'n drop. NEVER USED (release is done by tapping, which actually triggers a isSingleClick). Kept here for future-proofness.
             XTestFakeButtonEvent(display, mainMouseButton, False, 0);
         } else if (isScroll) {
             if (dy < 0) {