Fix E2E tests that are breaking VRT checks

[davidmenendez]

several tests were marked to skip in #7812

once the percy checks are running smoothly again those tests need to be modified to pass. the tests may be related to animation time as all of them seem to be components with animations on load.

ignore NotificationsPanel. those tests were failing due to the useOutsideClick sev 1 issue and will need to be addressed separately.

acceptance criteria

• review the tests that were marked with skip in fix: percy #7812
• modify SidePanel tests
• modify Datagrid tests
• modify PageHeader tests