Prevent blank screen; activity report data csv download - backend; next steps screen reader update

[kryswisnaskas]

Description of change
This is the frontend and backend changes to prevent the application to result in a blank screen when the author is null. It also prevents unapproved legacy reports from showing up in the "My Alerts" table.

This PR also addresses changes for the Next Steps Screen Reader update and backend changes for the CSV activity report download.

How to test

• pull changes
• create an activity report in draft
• set it's author to null in the database (or in the MyAlerts.js file)
• verify that the UI works without showing a blank screen (when not on this branch, blank screen will show)

Issue(s)

• closes https://ocio-jira.acf.hhs.gov/browse/TTAHUB-91
• closes https://ocio-jira.acf.hhs.gov/browse/TTAHUB-57
• closes https://ocio-jira.acf.hhs.gov/browse/TTAHUB-35

Checklist

• Meets issue criteria
• Code tested
• Meets accessibility standards (WCAG 2.1 Levels A, AA)
• [n/a] Documentation updated
  • API methods
  • Boundary and Data Flow Diagrams
  • Architectural Decision Records written for major infrastructure decisions with the Nygard template
  • OSCAL templates completed when security controls are implemented or modified