fixing ui tests

Author: nakul-py

src/diff/base-unified-diff.ts

@@ -137,6 +137,8 @@ export abstract class BaseUnifiedDiffManager {
    */
   public acceptAll(): void {
     // simply accept the current state
+    const sharedModel = this.getSharedModel();
+    this._originalSource = sharedModel.getSource();
     this.deactivate();
   }