fix(theme): green hero Share/Play/Queue glyphs in dark via shared .dd-accent-icon

Fold Session/Mix hero glyphs into the reusable accent-icon treatment so they reach
the glyph (beating .mud-secondary-text) green-accent in both themes; drop the dead
wrapper white rule and the redundant dark-only hero override. Light pixel-identical.

DeepDrftPublic.Client/Controls/WaveformVisualizerControlPopover.razor

@@ -29,7 +29,7 @@
    the shared WaveformVisualizerControlState and raises Changed; the visualizer bridge subscribes. This
    host only toggles open/closed and centers the panel — it stays purely presentational. *@
 
-<div class="dd-lava-lamp-trigger">
+<div class="dd-accent-icon">
     <MudTooltip Text="Visualizer settings">
         <MudIconButton Icon="@(_open ? DDIcons.LavaLampFilled : DDIcons.LavaLamp)"
                        Size="@IconSize"