Fix the DateCreated column issue in the Dashboard API response.

[bigdatasourav]

The Dashboard API is returning the below error.
https://pkg.go.dev/github.com/jianyuan/go-sentry/v2@v2.4.0/sentry#Dashboard

Error: parsing time "\"\"" as "\"2006-01-02T15:04:05Z07:00\"": cannot parse "\"" as "2006"