Add new constant variables for nursery and trial

GCP-10236

Reviewer: Aldrin Batac
Add new error message for invalid format of nursery/trial template

GCP-10236

Reviewer: Aldrin Batac
Add getters and setters for the errorMessage property

GCP-10236

Reviewer: Aldrin Batac
Show error message when the study template is in an invalid format

GCP-10236

Reviewer: Aldrin Batac
Add unit tests for showing error message when nursery or trial is in an invalid format

GCP-10236

Reviewer: Aldrin Batac