Client-side validation for serverless custom role names does not restrict spaces

[jeramysoucy]

Describe the bug: Serverless custom role assignments are stored as application privileges in cloud. This field does not allow whitespace characters. When attempting to assign a custom role with a space in the name/id, it will be rejected.

Steps to reproduce:

1. Create a search or security project in the QA environment
2. Create a custom role for that project with a space in the name
3. Confirm that no error has occurred (this will error once ES has updated their validation)
4. In cloud console, attempt to assign that role to a user in your org
5. Confirm that the assignment is rejected (500)

Expected behavior: In serverless, Kibana's validation of role names should restrict use of whitespace characters. This change must NOT apply to stateful Kibana, as it would be a breaking change.