refactor: make principal type optional in role assignments and clean up e2e tests#1884

Roopan-Microsoft merged 6 commits intoAzure-Samples:devAzure-Samples/chat-with-your-data-solution-accelerator:devfrom

Harmanpreet-Microsoft:dev-testHarmanpreet-Microsoft/chat-with-your-data-solution-accelerator:dev-testCopy head branch name to clipboard