Fix: VSE padding of missing media/data-block icon

The icon for missing media/data-block would be too close to the edges.

Decrease the size so it matches the size of the label and aligns with
the text baseline.

source/blender/editors/space_sequencer/sequencer_timeline_draw.cc

@@ -71,7 +71,7 @@ using namespace blender::ed::seq;
 
 #define MUTE_ALPHA 120
 
-constexpr float MISSING_ICON_SIZE = 16.0f;
+constexpr float MISSING_ICON_SIZE = 12.0f;
 
 struct StripDrawContext {
   Sequence *seq;