JP-3622 Update refpix step for NIR detectors to use convolution kernel

[penaguerrero]

Resolves JP-3622 Resolves RCAL-nnnn

Closes #

This PR addresses the changes needed to read a reference file for the NIR Optimized Convolution Kernel to be applied at the REFPIX step in the Detector1 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

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 67.59%. Comparing base (1e16207) to head (96a1de8). Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
src/stdatamodels/jwst/datamodels/conv_kernel.py	81.81%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #321 +/- ## ========================================== + Coverage 67.52% 67.59% +0.06% ========================================== Files 114 115 +1 Lines 5916 5931 +15 ========================================== + Hits 3995 4009 +14 - Misses 1921 1922 +1 ```

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