chore(deps): bump marrow-mailer from 4.0 to 4.0.3 (#6943)

Bumps [marrow-mailer](https://github.com/marrow/mailer) from 4.0 to 4.0.3.
- [Release notes](https://github.com/marrow/mailer/releases)
- [Commits](marrow/mailer@4.0.0...4.0.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: Areeb Jamal <jamal.areeb@gmail.com>

requirements/common.txt

@@ -37,7 +37,7 @@ qrcode==6.1
 python-magic==0.4.15
 python-dotenv==0.13.0
 python-geoip==1.2
-marrow.mailer==4.0
+marrow.mailer==4.0.3
 flask-cors==3.0.8
 python-pentabarf-xml==0.20
 python-geoip-geolite2==2015.303