Do casefolded comparison of netbios names (#14992)

There has been an uptick in users complaining about hitting the
activedirectory validation error that gets triggered when trying
to change the server netbiosname while it is enabled.
Make sure we're doing case-insensitive comparison for old and new
names and include the names in the ValidationError message.

src/middlewared/middlewared/plugins/activedirectory.py

@@ -123,12 +123,26 @@ async def nss_info_choices(self):
     async def update_netbios_data(self, old, new):
         must_update = False
         for key in ['netbiosname', 'netbiosalias']:
+            # netbios names are case-insensitive
             if key in new and old[key] != new[key]:
                 if old['enable']:
-                    raise ValidationError(
-                        f'activedirectory.{key}',
-                        'NetBIOS names may not be changed while service is enabled.'
-                    )
+                    if key == 'netbiosname' and new[key].casefold() != old[key].casefold():
+                        raise ValidationError(
+                            f'activedirectory.{key}',
+                            f'{old[key]} -> {new[key]}: NetBIOS name may not be changed while service is enabled.'
+                        )
+                    elif len(old[key]) != len(new[key]):
+                        raise ValidationError(
+                            f'activedirectory.{key}',
+                            f'{old[key]} -> {new[key]}: NetBIOS aliases may not be changed while service is enabled.'
+                        )
+                    else:
+                        for idx, alias in enumerate(old[key]):
+                            if old[key][idx].casefold() != new[key][idx].casefold():
+                                raise ValidationError(
+                                    f'activedirectory.{key}.{idx}',
+                                    f'{old[key][idx]} -> {new[key][idx]}: NetBIOS alias may not be changed while service is enabled.'
+                                )
 
                 must_update = True
                 break