* chore: move domain related functions to `packages/api`
* fix: isEmailDomainAllowed for case-insensitive domain matching
- Added tests to validate case-insensitive matching for email domains in various scenarios.
- Updated isEmailDomainAllowed function to convert email domains to lowercase for consistent comparison.
- Improved handling of null/undefined entries in allowedDomains.
* ci: Mock isEmailDomainAllowed in samlStrategy tests
- Added a mock implementation for isEmailDomainAllowed to return true in samlStrategy tests, ensuring consistent behavior during test execution.
* ci: Update import of isEmailDomainAllowed in ldapStrategy tests
- Changed the import of isEmailDomainAllowed from the domains service to the api package for consistency and to reflect recent refactoring.