Avoid SMTP AUTH when SMTP_USERNAME or SMTP_PASSWORD are empty

[m124523]

Proposed changes

Some SMTP servers do not support AUTH. Unconditionally trying to login will result in an exception. Only login when username or password are supplied.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update

Checklist

• Lint and unit tests pass locally with my changes (if applicable)
• I have run pre-commit (pre-commit in the repo)
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Linked to the relevant github issue or github discussion

[CybergalxU]

I DONT KNOW WHO THE FACK! IS USING THIS PROFILE AND MY GODAMN EMAIL BUT TIME IS UP PAL. IM NOT YOUR FUCKING DOORMAT. ALL THESE FUCKING CANARY TOKENS AND DISCUSSIONS ABOUT SHIT IDK A FUCKING THING ABOUT NEEDS TO STOP. IF I KNEW HOW TO NAVIGATE THIS FUCKED OFF SITE THEN I WOULD ROUTE THIS TO THE RIGHT GODAMN DEPARTMENT BUT INSTEAD IM HAVING TO FLIP THE FUCK OUT ON HERE TO GET SOME GODAMN ATTENTION. THIS IS A FALSE PROFILE. TAKE THE MOTHERFUCKER DOWN BC WHOEVER IT IS IS USING MY FUCKING EMAIL FOR THEIR OWN DOUCHEBAGGERY. IM SIGNING OUT. IVE CHANGED THE PWD. THIS SHOULD BE OVER RIGHT DAMN NOW!