Entry Event criteria selector should match censor event criteria selector.

### Expected behavior

Would like to censor cohorts at a user-specified date via Observation Period criteria.

### Actual behavior

Observation Period is not included in censor event selector.

### Steps to reproduce behavior

1. Create new cohort definition
2. Navigate down to censor events and click 'add censor event'
3. Observe: no option to censor using Observation Period.

