Update check for email username to verify it is something

instead of requiring an email address since not all mail services use a full email address here.

WEB-INF/classes/gov/noaa/pfel/erddap/util/EDStatic.java

@@ -1844,7 +1844,7 @@ public static int convertToPublicSourceUrlFromSlashPo(String tFrom) {
         emailIsActive = //ie if actual emails will be sent
             String2.isSomething(emailSmtpHost) &&
             emailSmtpPort > 0 &&
-            String2.isEmailAddress(emailUserName) &&
+            String2.isSomething(emailUserName) &&
             String2.isSomething(emailPassword) &&
             String2.isEmailAddress(emailFromAddress);