feat(core): add support for ShadowDOM v1 (#24718)

add a new ViewEncapsulation.ShadowDom option that uses the v1 Shadow DOM API to provide style encapsulation.

PR Close #24718

packages/compiler/src/core.ts

@@ -75,7 +75,8 @@ export interface Component extends Directive {
 export enum ViewEncapsulation {
   Emulated = 0,
   Native = 1,
-  None = 2
+  None = 2,
+  ShadowDom = 3
 }
 
 export enum ChangeDetectionStrategy {