fix rebuild_fits_rec_dtype for shaped columns

[braingram]

stdatamodels.util.rebuild_fits_rec_dtype appears to incorrectly handle unsigned integer columns with shapes. This PR updates rebuild_fits_rec_dtype and adds tests for this error.

Closes https://github.com/spacetelescope/stdatamodels/issues/206

Regression tests run with no errors: https://plwishmaster.stsci.edu:8081/blue/organizations/jenkins/RT%2FJWST-Developers-Pull-Requests/detail/JWST-Developers-Pull-Requests/963/pipeline

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:

Comparison is base (0ed03c2) 64.68% compared to head (e8a83fd) 64.70%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #213 +/- ## ========================================== + Coverage 64.68% 64.70% +0.01% ========================================== Files 102 102 Lines 5663 5666 +3 ========================================== + Hits 3663 3666 +3 Misses 2000 2000 ```

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