CI fixes: Replace type comparison with isinstance and increase lower pin for asdf

[braingram]

I noticed the CI fail on the main branch due to likely a ruff update (which caused a new E721 rule violation due to a comparison using a type instead of use of isinstance) and the oldest deps failing (due to the asdf dependency, jsonschema, updating).

This PR switches the type comparisons to calls to isinstance and increases the lower asdf version to 2.14.4.

Checklist for maintainers

• added entry in CHANGES.rst within the relevant release section
• updated or added relevant tests
• updated relevant documentation
• added relevant milestone
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below.
  How to run regression tests on a PR
• Make sure the JIRA ticket is resolved properly

[codecov]

Codecov Report

Patch coverage: 50.00% and project coverage change: -0.01% ⚠️

Comparison is base (e4defd6) 76.58% compared to head (eb6210d) 76.58%.

❗ Current head eb6210d differs from pull request most recent head 05bc5f1. Consider uploading reports for the commit 05bc5f1 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7801      +/-   ##
==========================================
- Coverage   76.58%   76.58%   -0.01%     
==========================================
  Files         456      456              
  Lines       36920    36920              
==========================================
- Hits        28275    28274       -1     
- Misses       8645     8646       +1     

Flag	Coverage Δ		*Carryforward flag
nightly	77.39% <ø> (-0.01%)	⬇️	Carriedforward from c9fa467

*This pull request uses carry forward flags. Click here to find out more.

Files Changed	Coverage Δ
jwst/assign_wcs/nirspec.py	93.90% <50.00%> (-0.14%)	⬇️

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[braingram]

Regression run started:
https://plwishmaster.stsci.edu:8081/job/RT/job/JWST-Developers-Pull-Requests/853/