fix(date-picker): update indigo elevations (#17288)

* fix(date-picker): update indigo elevations

* fix(grid): update excel and advanced filtering shadows

---------

Co-authored-by: Simeon Simeonoff <sim.simeonoff@gmail.com>

Author: didimmova

projects/igniteui-angular/core/src/core/styles/components/date-picker/_date-picker-theme.scss

@@ -25,10 +25,8 @@
         background: var-get($theme, 'content-background');
         overflow: hidden;
 
-        @if $variant == 'indigo' and  $theme-variant == 'light' {
+        @if $variant == 'indigo' {
             box-shadow: $border-shadow, elevation(5);
-        } @else if $variant == 'indigo' and $theme-variant == 'dark' {
-            box-shadow: $border-shadow, elevation(7);
         }
 
         igx-calendar,
@@ -49,10 +47,6 @@
         flex: 1 0 0;
         flex-direction: column;
         box-shadow: $border-shadow, elevation(3);
-
-        @if $variant == 'indigo' and $theme-variant == 'dark' {
-            box-shadow: $border-shadow, elevation(2);
-        }
     }
 
     %date-picker__buttons {

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

@@ -40,7 +40,7 @@
         flex-grow: 1;
 
         @if $variant == 'indigo' {
-            box-shadow: elevation(if($theme-variant == 'light', 3, 2)), 0 0 0 rem(1px) var-get($theme, 'excel-filtering-border-color');
+            box-shadow: elevation(3), 0 0 0 rem(1px) var-get($theme, 'excel-filtering-border-color');
 
             // TODO: The border-radius should not be hardcoded.
             border-radius: border-radius(rem(4px));

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

@@ -2692,7 +2692,7 @@
 
     %advanced-filtering-dialog {
 	    background: var-get($theme, 'filtering-dialog-background');
-        box-shadow: elevation(if($variant == 'indigo', if($theme-variant == 'light', 24, 23), 24));
+        box-shadow: elevation(24);
 
         @if $variant == 'material' or $variant == 'bootstrap' {
             border-radius: rem(4px);