adding validation while adding members in role resource

[shenda1]

Description

PR is raised to add validation to the role resource

ISSUE TYPE

• Bugfix Pull Request

RESOURCE OR DATASOURCE NAME

role resource

OUTPUT

# Checklist:

- [x] I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
- [x] I have verified that new and existing unit tests pass locally with my changes
- [ ] I have not allowed coverage numbers to degenerate
- [x] I have maintained at least 80% code coverage
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] I have added tests that prove my fix is effective or that my feature works
- [x] I have maintained backward compatibility


# How Has This Been Tested?
Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

- [ ] Unit tests
- [ ] Acceptance tests

![image](https://github.com/user-attachments/assets/ccb03bd2-10ac-4db5-85d8-faaabf41d7fe)

[shenda1]

[rounak-adhikary]

LGTM