fix(expansion-panel): bootstrap typography (#14855)

Author: SisIvanova

projects/igniteui-angular/src/lib/core/styles/typography/_bootstrap.scss

@@ -70,8 +70,8 @@
     ));
     @include expansion-panel-typography($categories: (
         title: 'h5',
-        description: 'body-2',
-        body: 'body-1'
+        description: 'subtitle-2',
+        body: 'body-2'
     ));
     @include excel-filtering-typography();
     @include icon-button-typography();