Validate date formats in advance nursery (the format should be yyyy-mm-dd)

Issue: GCP-9569

Reviewer: Chicka
Cleaned-up codes in the front-end for the trial and nursery manager (as reported by SonarQube)
1. Use of single quotes for string in JS files
2. Use of double quotes for html attributes (both in JS and HTML files)
3. Removed extra whitespaces
4. Removed unnecessary commented codes
5. Use of === and !== instead of == and !=

Issue: GCP-9569

Reviewer: Chezka Camille Arevalo