Feature/admin 2231 Eligibility Report

[HalcyonJAC]

Changes aligned with admin: Feature/2231 Improve Eligibility Report functionality.

• Update the callable function flagApplicationIssuesForExercise to generate the eligibility issues.
• Add a new flag flags.eligibilityIssuesMet in the application document to indicate if all eligibility issues are met.
• Add a created timestamp in the exercises/{EXERCISE_ID}/reports/characterIssues and exercises/{EXERCISE_ID}/reports/eligibilityIssues document which will be used to display on the admin site.
• Update Firestore indexes to enable the filter on the "Eligibility Issues" report page.