MOBILE-4060 theme: Fix ionic mixin when using add-root-selector

More info: ionic-team/ionic-framework#25264

Author: crazyserver

src/theme/helpers/ionic.functions.string.scss

@@ -147,9 +147,10 @@
     // If the selector contains :host it means it is targeting just the host
     // element so we can change it to look for host-context
     } @else if str-contains($selector, ":host") {
-      $list: append($list, ":host-context(#{$addHostSelector})", comma);
-    // If the selector does not contain host at all it is either a shadow
-    // or normal element so append both the dir check and host-context
+      $shadow-element: str-replace($selector, ":host", ":host-context(#{$addHostSelector})");
+      $list: append($list, $shadow-element, comma);
+      // If the selector does not contain host at all it is either a shadow
+      // or normal element so append both the dir check and host-context
     } @else {
       $list: append($list, "#{$addHostSelector} #{$selector}", comma);
       $list: append($list, ":host-context(#{$addHostSelector}) #{$selector}", comma);