Fix add authentication page (#16543)

* Fix add authentication page

There is a regression in #16199 whereby the add authentication page
fails to react to the change in selected type.

This is due to the String() method on the LoginSourceType which is ameliorated
with an Int() function being added.

Following on from this there are a few other related bugs.

Fix #16541

Signed-off-by: Andrew Thornton <art27@cantab.net>

services/auth/source/ldap/security_protocol.go

@@ -19,6 +19,11 @@ func (s SecurityProtocol) String() string {
 	return SecurityProtocolNames[s]
 }
 
+// Int returns the int value of the SecurityProtocol
+func (s SecurityProtocol) Int() int {
+	return int(s)
+}
+
 // SecurityProtocolNames contains the name of SecurityProtocol values.
 var SecurityProtocolNames = map[SecurityProtocol]string{
 	SecurityProtocolUnencrypted: "Unencrypted",