fix(button): redundant margin in bootstrap theme (#13866)

Author: SisIvanova

projects/igniteui-angular/src/lib/core/styles/components/button/_button-theme.scss

@@ -464,12 +464,6 @@
             map.get($items-gap, 'comfortable')
         );
 
-
-        @if ($variant == 'bootstrap') {
-            // important is needed to override the typography margins
-            margin: rem(4px) !important;
-        }
-
         igx-icon {
             --component-size: var(--ig-size, var(--ig-size-large));
             display: flex;

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

@@ -459,6 +459,11 @@
         margin-inline: pad-inline(rem(4px), rem(4px), rem(16px));
         margin-block-start: 0;
 
+        @if $bootstrap-theme {
+            // important is needed to override the typography margins
+            margin-block-end: rem(4px) !important;
+        }
+
         igx-icon {
             width: var(--igx-icon-size, #{rem(18px)});
             height: var(--igx-icon-size, #{rem(18px)});

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

@@ -2660,6 +2660,12 @@
         [igxIconButton] {
             --ig-size: 1;
         }
+
+        @if ($variant == 'bootstrap') {
+            [igxButton] {
+                margin: rem(4px);
+            }
+        }
     }
 
     %igx-grid__filtering-dropdown-items {