Orad/fix emulator bug repeat call

[odunbar]

Purpose

Closes #280

Content

• adds a warning when asked to build_models! with a machine learning tool that is already built.
• skips the build stage entirely
• adds unit tests

---

• [x] I have read and checked the items on the review checklist.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (a621a04) 88.09% compared to head (3e96ca4) 88.26%. Report is 15 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #281 +/- ## ========================================== + Coverage 88.09% 88.26% +0.16% ========================================== Files 7 8 +1 Lines 1134 1184 +50 ========================================== + Hits 999 1045 +46 - Misses 135 139 +4 ```

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