membershipworks/ucsAccounts: Don't set email if empty in MembershipWorks

membershipworks/tasks/ucsAccounts.py

@@ -90,13 +90,15 @@ async def sync_member(user_mod, member: Member):
             # "userexpiry": member["Renewal Date"],
             # "pwdChangeNextLogin": "1", # User has to change password on next login
             # "sambaLogonHours": "", # Permitted times for Windows logins
-            "e-mail": [member.email],  # ([]) E-mail address
             "phone": [member.phone],  # Telephone number
             # "PasswordRecoveryMobile": member["Phone"], # Mobile phone number
             "PasswordRecoveryEmail": member.email,
         }
     )
 
+    if member.email:
+        user.props["e-mail"] = [member.email]  # ([]) E-mail address
+
     new_groups = [
         f"cn={sanitize_group_name(flag.name)},{GROUP_BASE}"
         async for flag in member.flags.filter(