Allow usage of Sendgrid without Subusers support

bubble-server/src/main/java/bubble/cloud/email/SendgridSmtpEmailDriver.java

@@ -25,6 +25,9 @@ import static org.cobbzilla.util.json.JsonUtil.json;
 import static org.cobbzilla.util.security.CryptoUtil.generatePassword;
 import static org.cobbzilla.util.string.StringUtil.repeat;
 
+/**
+ * Only to be used with Sendgrid account with Subusers supported!
+ */
 public class SendgridSmtpEmailDriver extends SmtpEmailDriver {
     public static final String SG_API_BASE = "https://api.sendgrid.com/v3/";
 

bubble-server/src/main/java/bubble/cloud/email/SmtpEmailDriver.java

@@ -27,7 +27,6 @@ public class SmtpEmailDriver extends CloudServiceDriverBase<EmailDriverConfig> i
     protected static final String SENDGRID_SMTP = "smtp.sendgrid.net";
 
     private static final List<String> SEPARATE_DRIVERS_SMTPS = new ArrayList<>();
-    static { SEPARATE_DRIVERS_SMTPS.add(SENDGRID_SMTP); }
 
     protected static final String PARAM_USER = "user";
     protected static final String PARAM_PASSWORD = "password";
@@ -56,6 +55,7 @@ public class SmtpEmailDriver extends CloudServiceDriverBase<EmailDriverConfig> i
     }
 
     protected boolean isServiceCompatible(final String serviceHost) {
+        // Allow even Sendgrid here if Subusers are not supported for specified API key
         return !SEPARATE_DRIVERS_SMTPS.contains(serviceHost);
     }