Breaking: #63056 - Remove Template Selection Hack

See Issue #63056

Description

There has been an ancient hack for the former “freesite” extension, which enabled selection of the template via GET variable. This technique is outdated and has been removed.

Impact

Any extension using this hack will not be able to select the template this way anymore.

Affected installations

Installations with third party extensions using the hack.

Migration

No migration path intended.