BUG: Fix load data after imviz.app does not show last loaded data

[pllim]

Description

This pull request is to fix #1126

Checklist for package maintainer(s)

This checklist is meant to remind the package maintainer(s) who will review this pull request of some common things to look for. This list is not exhaustive.

• Are two approvals required? Branch protection rule does not check for the second approval. If a second approval is not necessary, please apply the trivial label.
• Do the proposed changes actually accomplish desired goals? Also manually run the affected example notebooks, if necessary.
• Do the proposed changes follow the STScI Style Guides?
• Are tests added/updated as required? If so, do they follow the STScI Style Guides?
• Are docs added/updated as required? If so, do they follow the STScI Style Guides?
• Did the CI pass? If not, are the failures related?
• Is a change log needed? If yes, is it added to CHANGES.rst?
• Is a milestone set? Milestone is only currently required for PRs related to Imviz MVP.
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)?

[codecov]

Codecov Report

Merging #1178 (bb74d8d) into main (be1d987) will increase coverage by 0.09%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #1178      +/-   ##
==========================================
+ Coverage   76.37%   76.47%   +0.09%     
==========================================
  Files          87       87              
  Lines        6723     6728       +5     
==========================================
+ Hits         5135     5145      +10     
+ Misses       1588     1583       -5     

Impacted Files	Coverage Δ
jdaviz/app.py	90.13% <100.00%> (-0.16%)	⬇️
jdaviz/configs/imviz/helper.py	98.70% <100.00%> (+0.02%)	⬆️
jdaviz/configs/imviz/plugins/parsers.py	100.00% <100.00%> (ø)
...configs/default/plugins/data_tools/file_chooser.py	69.14% <0.00%> (+3.42%)	⬆️

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[pllim]

The failure in jdaviz/configs/imviz/tests/test_simple_aper_phot.py is unrelated and is going to be fixed by #1138

[camipacifici]

Works and also fixes the problem I was seeing with black/gray images when blinking.

[pllim]

I think one happy PO = two approvals. So I am going to merge this so we can go back to reviewing the other fix at #1164. 😸 #yolo