[RF][HS3] bugfix for external constraint handling

[cburgard]

This Pull request:

Makes sure the external constraints exported are re-imported successfully.

Changes or fixes:

Checklist:

• tested changes locally
• updated the docs (if necessary)

This PR fixes #

[guitargeek]

Hi @cburgard! Thanks for the PR. Do you maybe have a small example with a problematic workspace that can be turned into a unit test? I think adding more tests would help a lot to prevent future regressions!

[github-actions]

Test Results

     6 files       6 suites   23h 16m 39s ⏱️
 5 298 tests  5 278 ✅ 20 💤 0 ❌
18 494 runs  18 494 ✅  0 💤 0 ❌

Results for commit e2069fc.

[cburgard]

Hi @guitargeek ,
thanks for the quick reply. I'm currently working on a paper that uses this. I'll happily provide the workspace for the paper once it's out, but that will need a few more weeks.