fix(button-toggle): fix color for selected button toggle and selected disabled button toggle (#3418)

Fixes #3382

Author: tinayuangao

src/lib/button-toggle/_button-toggle-theme.scss

@@ -23,16 +23,16 @@
   }
 
   .mat-button-toggle-checked {
-    background-color: mat-color($mat-grey, 300);
+    background-color: mat-color($background, selected-button);
     color: mat-color($foreground, base);
   }
 
   .mat-button-toggle-disabled {
-    background-color: map_get($mat-grey, 200);
+    background-color: mat-color($background, disabled-button-toggle);
     color: mat-color($foreground, disabled-button);
 
     &.mat-button-toggle-checked {
-      background-color: mat-color($mat-grey, 400);
+      background-color: mat-color($background, selected-disabled-button);
     }
   }
 }

src/lib/core/theming/_palette.scss

@@ -656,6 +656,9 @@ $mat-light-theme-background: (
   disabled-button: $black-12-opacity,
   raised-button: white,
   focused-button: $black-6-opacity,
+  selected-button: map_get($mat-grey, 300),
+  selected-disabled-button: map_get($mat-grey, 400),
+  disabled-button-toggle: map_get($mat-grey, 200),
 );
 
 // Background palette for dark themes.
@@ -669,6 +672,9 @@ $mat-dark-theme-background: (
   disabled-button: $white-12-opacity,
   raised-button: map-get($mat-grey, 800),
   focused-button: $white-6-opacity,
+  selected-button: map_get($mat-grey, 900),
+  selected-disabled-button: map_get($mat-grey, 800),
+  disabled-button-toggle: map_get($mat-grey, 1000),
 );
 
 // Foreground palette for light themes.