Add more validation for "generate timesheet"

[gianklug]

              r.get("review") === data.review && 
              r.get("notBillable") === data.notBillable && 
              !r.get("verfiedBy") && 
              !r.get("isDeleted")

ig we can add the review and non billable checks but I don't think such an edge-case would ever occur.

same goes for already verified reports; if one is verified on one day, why would anyone create a second activity.

After all this seems to me like very bad client-side validation

Originally posted by @gianklug in #24 (comment)

[gianklug]

We need to check for these flags anyways when generating the timesheet. As of right now, these are not even checked.