defaultTheme deprecation warning should link to change record

Problem/Motivation

I noticed that the deprecation warning about defaultTheme links not to the change record, but to the issue. I think it would be more helpful to link to the change record, which has the relevant information in a condensed form, rather than the issue which loads slower because it has over 130 comments, and would require searching for the recommendations.

Three nodes relate to this deprecation, the change record: https://www.drupal.org/node/3083055
and these two issues
https://www.drupal.org/node/2352949
and https://www.drupal.org/project/drupal/issues/3082655

Proposed resolution

Change the node id 2352949 to 3083055 in the deprecation warning.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet