PBB-32 Fix suffix addition in FNG pipeline for custom projects
Due to an issue in GitLab where escaped variables are not correctly
passed to child pipelines, a workaround is required.
As a result, we use raw variables.
The DEFERRED_RELEASE_VERSION variable was introduced for this purpose.
However, for custom builds, we have an additional place where we modify
the DEFERRED_RELEASE_VERSION variable to add a suffix.
Therefore, extra interim variables need to be added to handle the workaround
and ensure we get the raw variable in the end.
Edited by Andrii Sosiuk