[Outlook] Feature: Office365 multi-user support

[ilyasabdellaoui]

Introduced BaseOffice365User abstract base class to standardize Office 365 user handling. Added MultiOffice365Users to manage multiple emails from config. Added client_emails (comma-separated) in OutlookDataSource config. Resolved issue with fetching too many users causing SMTP server not found error.

Closes #2843

Checklists

Pre-Review Checklist

• this PR does NOT contain credentials of any kind, such as API keys or username/passwords (double check config.yml.example)
• this PR has a meaningful title
• this PR links to all relevant github issues that it fixes or partially addresses
• this PR has a thorough description
• Covered the changes with automated tests
• Tested the changes locally
• Considered corresponding documentation changes
• Contributed any configuration settings changes to the configuration reference
• if you added or changed Rich Configurable Fields for a Native Connector, you made a corresponding PR in Kibana

[cla-checker-service]

💚 CLA has been signed

[seanstory]

buildkite test this

[seanstory]

This is great! Thanks for submitting a patch! I've left a few comments, but overall I think this is a pretty clean approach and solves a clear ask.

Outside of the below comments, I'd also request that you change the

Closes #2843

in your PR description to use "Relates to" or "Part of", since another part of the issue you filed is that the current solution is limited to 999 users. I expect that's something we can better control with the graph API and another separate configuration, for folks who want "all users", and have more than 999.

[seanstory]

I suggest making these their own test functions. That way, any failures are more easily identifyable, and they can have more focused test names to help the reader understand what's being tested.

[seanstory]

The tests pass, but the linter is currently failing. You can fix this by running make autoformat when you're done making changes.

[ilyasabdellaoui]

in your PR description to use "Relates to" or "Part of", since another part of the issue you filed is that the current solution is limited to 999 users. I expect that's something we can better control with the graph API and another separate configuration, for folks who want "all users", and have more than 999.

@seanstory After rechecking the code, I realized I was mistaken in my initial description. The code isn't limited to fetching the top 999 users—it handles pagination using the @odata.nextLink property from the Microsoft Graph API, which retrieves all users. I missed that detail. I'll update my issue description to reflect the correct behavior.

connectors/connectors/sources/outlook.py

Lines 411 to 429 in 6e74c3a

	async def get_users(self):
	access_token = await self._fetch_token()
	url = f"https://graph.microsoft.com/v1.0/users?$top={TOP}"
	while True:
	try:
	async with self._get_session.get(
	url=url,
	headers={
	"Authorization": f"Bearer {access_token}",
	"Content-Type": "application/json",
	},
	) as response:
	json_response = await response.json()
	yield json_response
	url = json_response.get("@odata.nextLink")
	if url is None:
	break
	except Exception:
	raise

[seanstory]

buildkite test this

[ilyasabdellaoui]

buildkite test this

Lint still fails due to async-related issues. Autoformat doesn't solve the lint errors. I'll investigate further after completing test functions. If unable to resolve, I'll seek assistance