replace usage of copy_arrays=True with memmap=False

[zacharyburnett]

follow-on to asdf-format/asdf#1797

Checklist for PR authors (skip items if you don't have permissions or they are not applicable)

• 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
• All comments are resolved
• Make sure the JIRA ticket is resolved properly

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 60.36%. Comparing base (4c50426) to head (573667b).

Files with missing lines	Patch %	Lines
jwst/lib/set_telescope_pointing.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8660   +/-   ##
=======================================
  Coverage   60.36%   60.36%           
=======================================
  Files         372      372           
  Lines       38325    38326    +1     
=======================================
+ Hits        23136    23137    +1     
  Misses      15189    15189           

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[zacharyburnett]

regtest: https://github.com/spacetelescope/RegressionTests/actions/runs/9994022959

[braingram]

LGTM.