MCR-4888: Add update email settings api

[JasonLin0991]

Summary

MCR-4888

AC:

• This API an only be called by Admin user, allows update of the new fields.
• Enforce email validations here   - create a zod schema type EmailSettings to validate with z.string().email().optional() for each item in the string array.
• We can go ahead and error if emails not sent in for updates of any field, no need for partial updates, just make sure errors tells you which field or email to fix.

Related issues

Screenshots

Test cases covered

settings.test.ts
Tests the Zod custom validator for emailSettingsSchema

• 'should validate emails with display names'
• 'should validate plain emails'
• 'should trim white space of emails'
• 'should reject empty email settings'
• 'should reject invalid email format'
• 'should reject empty email arrays'
• 'should reject malformed email aliases'

updateEmailSettings.test.ts
resolver tests

• 'updates email settings'
• 'errors when on failed email validations'
• 'errors when user is not an admin'

QA guidance

[haworku]

@JasonLin0991 ⭐on covering the test cases