Update instructor-request-form.component.ts

[omarayman23]

[Issue #13371 Add validation for email input in feedback form [#13365] Fixes #13371 Outline of Solution This change adds client-side (front-end) email format validation to the instructor account request form.

• Problem: The form only checked if the email field was empty, but not if the format was valid (e.g., test@test would be accepted). The user would only see an error after submitting.
• Solution: By adding Angular's built-in Validators.email, the form now provides immediate feedback to the user if the email format is invalid.

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