dns/ddclient: fix rendering template when if but no interface

Use a validation in this case as it seems to be a hard requirement.
Also shuffle the dialog a little to move the fields into a more
logical sequence.

dns/ddclient/src/opnsense/mvc/app/controllers/OPNsense/DynDNS/forms/dialogAccount.xml

@@ -5,6 +5,11 @@
         <type>checkbox</type>
         <help>Enable this virtual server</help>
     </field>
+    <field>
+        <id>account.description</id>
+        <label>Description</label>
+        <type>text</type>
+    </field>
     <field>
         <id>account.service</id>
         <label>Service</label>
@@ -71,6 +76,11 @@
         <type>dropdown</type>
         <help>How to determine the address to use for this host</help>
     </field>
+    <field>
+        <id>account.interface</id>
+        <label>Interface to monitor</label>
+        <type>dropdown</type>
+    </field>
     <field>
         <id>account.checkip_timeout</id>
         <label>Check ip timeout</label>
@@ -84,14 +94,4 @@
         <help>Force update using HTTPS, please note setting this option will enforce https updates on all accounts
         as ddclient only supports SSL=yes on a global level (the check ip service may still use HTTP on other services)</help>
     </field>
-    <field>
-        <id>account.interface</id>
-        <label>Interface to monitor</label>
-        <type>dropdown</type>
-    </field>
-    <field>
-        <id>account.description</id>
-        <label>Description</label>
-        <type>text</type>
-    </field>
 </form>

dns/ddclient/src/opnsense/mvc/app/models/OPNsense/DynDNS/DynDNS.xml

@@ -153,6 +153,11 @@
                         <web_zoneedit>zoneedit</web_zoneedit>
                         <if>Interface</if>
                     </OptionValues>
+                    <Constraints>
+                        <check001>
+                            <reference>interface.check001</reference>
+                        </check001>
+                    </Constraints>
                 </checkip>
                 <checkip_timeout type="IntegerField">
                     <default>10</default>
@@ -167,6 +172,14 @@
                 <interface type="InterfaceField">
                     <Required>N</Required>
                     <multiple>N</multiple>
+                    <Constraints>
+                        <check001>
+                            <ValidationMessage>An interface is required for the selected check method</ValidationMessage>
+                            <type>SetIfConstraint</type>
+                            <field>checkip</field>
+                            <check>if</check>
+                        </check001>
+                    </Constraints>
                 </interface>
                 <description type="TextField">
                     <Required>N</Required>

dns/ddclient/src/opnsense/scripts/ddclient/lib/account/cloudflare.py

@@ -172,4 +172,4 @@ class Cloudflare(BaseAccount):
                 )
 
 
-        return False
+        return False