Remove createTime & readTime from DocumentSnapshot

These were added to the API before I knew they could have been queried internally.

Author: DellaBitta

common/api-review/firestore-lite.api.md

@@ -146,14 +146,10 @@ export class DocumentReference<AppModelType = DocumentData, DbModelType extends
 // @public
 export class DocumentSnapshot<AppModelType = DocumentData, DbModelType extends DocumentData = DocumentData> {
     protected constructor();
-    // (undocumented)
-    get createTime(): Timestamp | undefined;
     data(): AppModelType | undefined;
     exists(): this is QueryDocumentSnapshot<AppModelType, DbModelType>;
     get(fieldPath: string | FieldPath): any;
     get id(): string;
-    // (undocumented)
-    get readTime(): Timestamp | undefined;
     get ref(): DocumentReference<AppModelType, DbModelType>;
 }
 

common/api-review/firestore.api.md

@@ -172,15 +172,11 @@ export class DocumentReference<AppModelType = DocumentData, DbModelType extends
 // @public
 export class DocumentSnapshot<AppModelType = DocumentData, DbModelType extends DocumentData = DocumentData> {
     protected constructor();
-    // (undocumented)
-    get createTime(): Timestamp;
     data(options?: SnapshotOptions): AppModelType | undefined;
     exists(): this is QueryDocumentSnapshot<AppModelType, DbModelType>;
     get(fieldPath: string | FieldPath, options?: SnapshotOptions): any;
     get id(): string;
     readonly metadata: SnapshotMetadata;
-    // (undocumented)
-    get readTime(): Timestamp;
     get ref(): DocumentReference<AppModelType, DbModelType>;
     // (undocumented)
     toJSON(): object;

packages/firestore/src/lite-api/snapshot.ts

@@ -330,14 +330,6 @@ export class DocumentSnapshot<
     );
   }
 
-  get createTime(): Timestamp | undefined {
-    return this._document?.createTime.toTimestamp();
-  }
-
-  get readTime(): Timestamp | undefined {
-    return this._document?.readTime.toTimestamp();
-  }
-
   /**
    * Signals whether or not the document at the snapshot's location exists.
    *