[SafetyCheck] Fix intercepting keys

The functionality for ctrl+z introduced by CL 4037744 captured keys, and
ran preventDefault() on the associated event, intercepting and blocking
any key presses on the page. This CL removes those calls and fixes this
issue.

Bug: 1345920, 1392664
Change-Id: I4285097bdce0cc1b7746a0014b684b6d3425421f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4071806
Reviewed-by: Rainhard Findling <rainhard@chromium.org>
Commit-Queue: Tom Van Goethem <tov@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1078523}

chrome/browser/resources/settings/site_settings/review_notification_permissions.ts

@@ -352,7 +352,6 @@ export class SettingsReviewNotificationPermissionsElement extends
   private onKeyDown_(e: KeyboardEvent) {
     // Only allow undoing via ctrl+z when the undo toast is opened.
     if (!this.$.undoToast.open) {
-      e.preventDefault();
       return;
     }
 
@@ -365,7 +364,6 @@ export class SettingsReviewNotificationPermissionsElement extends
      * and ctrl on mac).
      */
     if (e.key !== 'z') {
-      e.preventDefault();
       return;
     }
     const excludedModifiers = [e.altKey, e.shiftKey];
@@ -379,7 +377,6 @@ export class SettingsReviewNotificationPermissionsElement extends
     // </if>
     if (!excludedModifiers.some(Boolean) && targetModifier) {
       this.undoLastAction();
-      e.preventDefault();
     }
   }