Make AssuranceErrorDisplayActivity extend Activity

[prudrabhat]

A recent change that was done to remove themes missed switching AssuranceErrorDisplayActivity extend Activity. Switch it now.

Description

Assurance now does not expose/use themes. So all references to activities that require a theme should be switched to Activity. A recent change that was done to remove themes missed switching AssuranceErrorDisplayActivity extend Activity. Switch it now.

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots (if appropriate):

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] I have signed the Adobe Open Source CLA.
• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.