chore(*): Extract hardcoded styles in class.

Author: MKirova

projects/igniteui-angular/src/lib/core/styles/components/grid/_grid-component.scss

@@ -296,6 +296,10 @@
             @extend %igx-grid__td--edited !optional;
         }
 
+        @include e(td, $m: merged) {
+            @extend %igx-grid__td--merged !optional;
+        }
+
         @include e(td, $m: editing) {
             @extend %igx-grid__td--editing !optional;
         }

projects/igniteui-angular/src/lib/core/styles/components/grid/_grid-theme.scss

@@ -1872,6 +1872,11 @@
         }
     }
 
+    %igx-grid__td--merged {
+        z-index: 1;
+        grid-row: 1 / -1;
+    }
+
     %igx-grid__tr--deleted {
         %grid-cell-text {
             font-style: italic;
@@ -2084,7 +2089,7 @@
 
         .sort-icon {
             color: var-get($theme, 'header-selected-text-color');
-	        
+
             ::after {
                 background: var-get($theme, 'header-selected-background');
             }
@@ -2112,15 +2117,15 @@
         &%igx-grid-th--sorted {
             .sort-icon {
                 color: var-get($theme, 'header-selected-text-color');
-	            
+
 	            > igx-icon {
 		            color: inherit;
 	            }
 
                 &:focus,
                 &:hover {
                     color: var-get($theme, 'header-selected-text-color');
-	                
+
 	                > igx-icon {
 		                color: inherit;
 	                }
@@ -2177,14 +2182,14 @@
         .sort-icon {
             opacity: 1;
             color: var-get($theme, 'sorted-header-icon-color');
-	        
+
 	        > igx-icon {
 		        color: inherit;
 	        }
 
             &:hover {
                 color: var-get($theme, 'sortable-header-icon-hover-color');
-	            
+
 	            > igx-icon {
 		            color: inherit;
 	            }

projects/igniteui-angular/src/lib/grids/grid/grid-row.component.html

@@ -195,8 +195,6 @@
     [active]="isCellActive(col.visibleIndex)"
     [cellSelectionMode]="grid.cellSelection"
     [displayPinnedChip]="shouldDisplayPinnedChip(col.visibleIndex)"
-    [style.gridRow]="'1 / -1'"
-    [style.zIndex]="data.cellMergeMeta.get(col.field).rowSpan"
     [style.min-width]="col.resolvedWidth"
     [style.max-width]="col.resolvedWidth"
     [style.flex-basis]="col.resolvedWidth"