CheatSearch: Update Current Values at end of frame

At the end of each frame automatically update the Current Value for
visible table rows in the selected and visible CheatSearchWidget (if
any). Also update all Current Values in all CheatSearchWidgets when the
State changes to Paused.

Only updating visible table rows serves to minimize the performance cost
of this feature. If the user scrolls to an un-updated cell it will
promptly be updated by either the next VIEndFieldEvent or the State
transitioning to Paused.

Source/Core/Core/HW/VideoInterface.cpp

@@ -33,6 +33,7 @@
 
 #include "VideoCommon/VideoBackendBase.h"
 #include "VideoCommon/VideoConfig.h"
+#include "VideoCommon/VideoEvents.h"
 
 namespace VideoInterface
 {
@@ -839,6 +840,7 @@ void VideoInterfaceManager::EndField(FieldType field, u64 ticks)
     OutputField(field, ticks);
 
   g_perf_metrics.CountVBlank();
+  VIEndFieldEvent::Trigger();
   Core::OnFrameEnd();
 }