Refactor release workflow (extra-bicep-artifacts stage)

## Situation

In the release workflow we have a stage where we compile bicep artefacts `CreateExtraBicepArtifacts`

If this fails, it blocks the release.

## Solution

We need to refactor the `CreateExtraBicepArtifacts` stage into its own resuable workflow, and call it during PR to ensure release won't fail.
As the stage creates artefacts we will need to introduce a new parameter to opt out of artefact creation.

Start by locating the release workflow and its CreateExtraBicepArtifacts stage. Refactor that stage into a reusable workflow, invoke it during pull requests, and add the parameter needed to opt out of artifact creation; done means pull-request validation catches failures without blocking releases.

Written by the indexing model from the issue text.