update test mapping emicorr reference files to EmiModel

[braingram]

The test_schema_against_crds tests are failing on main: https://github.com/spacetelescope/stdatamodels/actions/runs/8096660095/job/22125905730 due to a lack of mapping between the now-available emicorr reference file and the EmiModel model used for this file type.

This PR updates the test for the mapping in the test to map emicorr to EmiModel.

Checklist

• [ ] added entry in CHANGES.rst (either in Bug Fixes or Changes to API)
• [ ] updated relevant tests
• [ ] updated relevant documentation
• [ ] updated relevant milestone(s)
• [ ] added relevant label(s)

[codecov[bot]]

Codecov Report

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

Project coverage is 64.87%. Comparing base (4d7c3a6) to head (5899200). Report is 4 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #269 +/- ## ========================================== + Coverage 64.84% 64.87% +0.03% ========================================== Files 103 104 +1 Lines 5694 5699 +5 ========================================== + Hits 3692 3697 +5 Misses 2002 2002 ```

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