backends: set needsFrame for manually scheduled frames

src/backend/Headless.cpp

@@ -55,6 +55,7 @@ Hyprutils::Memory::CSharedPointer<IBackendImplementation> Aquamarine::CHeadlessO
 
 void Aquamarine::CHeadlessOutput::scheduleFrame() {
     // FIXME: limit fps to the committed framerate.
+    needsFrame = true;
 
     if (frameScheduled)
         return;

src/backend/Wayland.cpp

@@ -723,6 +723,8 @@ Hyprutils::Math::Vector2D Aquamarine::CWaylandOutput::cursorPlaneSize() {
 }
 
 void Aquamarine::CWaylandOutput::scheduleFrame() {
+    needsFrame = true;
+
     if (frameScheduled)
         return;
 

src/backend/drm/DRM.cpp

@@ -1304,6 +1304,8 @@ void Aquamarine::CDRMOutput::moveCursor(const Vector2D& coord) {
 }
 
 void Aquamarine::CDRMOutput::scheduleFrame() {
+    needsFrame = true;
+
     if (connector->isPageFlipPending || connector->frameEventScheduled)
         return;