Fix Explorer reference export on promotion

Since changes for NXP-29742, export on promotion is failing because the version cannot be parsed from the trigger build description.

The export code expects a description "Release 11.2 from build 11.2.13" when triggered from a Nuxeo release, or "Release 11.2" when triggered from a JSF release, but the actual description in this case is "Release 2021.24.3".