Tachyon: Remove spurious CSS for stat-card (#142487)

Author: StanFromIreland

Lib/profiling/sampling/_heatmap_assets/heatmap.css

@@ -75,18 +75,6 @@
   overflow: hidden;
 }
 
-.stat-card::before {
-  content: '';
-  position: absolute;
-  top: 0;
-  left: 0;
-  right: 0;
-  height: 3px;
-  background: linear-gradient(90deg, var(--python-blue), var(--python-gold));
-  opacity: 0;
-  transition: opacity var(--transition-fast);
-}
-
 .stat-card:nth-child(1) { --i: 0; --card-color: 55, 118, 171; }
 .stat-card:nth-child(2) { --i: 1; --card-color: 40, 167, 69; }
 .stat-card:nth-child(3) { --i: 2; --card-color: 255, 193, 7; }
@@ -101,10 +89,6 @@
   box-shadow: 0 4px 16px rgba(var(--card-color), 0.15);
 }
 
-.stat-card:hover::before {
-  opacity: 1;
-}
-
 .stat-icon {
   width: 40px;
   height: 40px;