chore: 🤖 add callback_url to oidc form

addons/core/translations/form/en-us.yaml

@@ -112,3 +112,6 @@ key:
   label: Key
 value:
   label: Value
+callback_url:
+  label: Callback URL
+  help: The URL to which the third-party provider sends the authentication response.  Paste this into the provider configuration.

ui/admin/app/components/form/auth-method/oidc/index.hbs

@@ -629,6 +629,16 @@
     {{/if}}
   </form.input>
 
+  {{#unless @model.isNew}}
+    <form.input
+      @value={{@model.attributes.callback_url}}
+      @label={{t 'form.callback_url.label'}}
+      @helperText={{t 'form.callback_url.help'}}
+      readonly={{true}}
+      @disabled={{true}}
+    />
+  {{/unless}}
+
   <form.actions
     @disabled={{if @model.cannotSave @model.cannotSave}}
     @enableEditText={{t 'actions.edit-form'}}