refactor(docs-infra): change unused classes to interfaces (#29553)

PR Close #29553

aio/src/app/custom-elements/contributor/contributors.model.ts

@@ -1,15 +1,15 @@
-export class ContributorGroup {
+export interface ContributorGroup {
   name: string;
   order: number;
   contributors: Contributor[];
 }
 
-export class Contributor {
+export interface Contributor {
   group: string;
   name: string;
   picture?: string;
   website?: string;
   twitter?: string;
   bio?: string;
-  isFlipped ? = false;
+  isFlipped?: boolean;
 }