refactor: Remove MDC theme's deep-get, used sass:map's get API instead.

BREAKING CHANGE: Removed `deep-get()` API from mdc-theme, use `sass:map`'s get() API instead.

PiperOrigin-RevId: 345257138

Author: abhiomkar

packages/mdc-theme/_theme.scss

@@ -180,24 +180,3 @@
     );
   }
 }
-
-/// Perform a recursive map.get on a nested map structure
-/// Returns a value, or `null` if `$map` does not contain `$path`.
-///
-/// @example scss
-///   $color: deep-get((foo: (bar: black)), (foo, bar));
-///   $color === black;
-///
-/// @param {Map} $map - Map to recurse down
-/// @param {List} $path - List of keys to traverse the map
-/// @return {*} The deep value or `null`
-@function deep-get($map: (), $keys: ()) {
-  $result: $map;
-  @each $key in $keys {
-    $result: map.get($result, $key);
-    @if $result == null {
-      @return null;
-    }
-  }
-  @return $result;
-}