RCAL-632: add unit tests for additional methods.

[mairanteodoro]

Resolves RCAL-632

This PR addresses adding new methods required by the resampling step for RomanCal and its corresponding unit tests.

Notes

• For JWST, the update_s_region_imaging is calling wcs.footprint with center=True, which means the footprint coordinates will be those of the center of the pixels. However, since we're using a bounding box to calculate the footprint, it would make sense to use the vertices of the pixels instead of the center, which is the default behavior of the wcs.footprint method. Therefore, we added the option to pass the center parameter to update_s_region_imaging in order to make the unit tests pass the correct way of using wcs.footprint.

• This PR is blocking the PR for the resample step.

Checklist

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

[codecov[bot]]

Codecov Report

Patch coverage: 97.82% and project coverage change: +0.15% :tada:

Comparison is base (8acd94c) 74.96% compared to head (4644bdc) 75.12%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## stcal-alignment #190 +/- ## =================================================== + Coverage 74.96% 75.12% +0.15% =================================================== Files 33 34 +1 Lines 6248 6291 +43 =================================================== + Hits 4684 4726 +42 - Misses 1564 1565 +1 ``` | [Files Changed](https://app.codecov.io/gh/spacetelescope/stcal/pull/190?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spacetelescope) | Coverage Δ | | |---|---|---| | [src/stcal/alignment/util.py](https://app.codecov.io/gh/spacetelescope/stcal/pull/190?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spacetelescope#diff-c3JjL3N0Y2FsL2FsaWdubWVudC91dGlsLnB5) | `81.66% <94.73%> (+1.54%)` | :arrow_up: | | [src/stcal/\_\_init\_\_.py](https://app.codecov.io/gh/spacetelescope/stcal/pull/190?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spacetelescope#diff-c3JjL3N0Y2FsL19faW5pdF9fLnB5) | `100.00% <100.00%> (ø)` | | | [tests/test\_alignment.py](https://app.codecov.io/gh/spacetelescope/stcal/pull/190?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=spacetelescope#diff-dGVzdHMvdGVzdF9hbGlnbm1lbnQucHk=) | `100.00% <100.00%> (ø)` | |

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