Fix error in image viewer when using update_values_from_data

[astrofrog]

Fixes #1854

[codecov]

Codecov Report

Merging #1975 into master will increase coverage by 0.13%.
The diff coverage is 94.11%.

@@            Coverage Diff            @@
##           master   #1975      +/-   ##
=========================================
+ Coverage   87.47%   87.6%   +0.13%     
=========================================
  Files         244     244              
  Lines       21746   21857     +111     
=========================================
+ Hits        19022   19148     +126     
+ Misses       2724    2709      -15

Impacted Files	Coverage Δ
glue/core/data.py	90.37% <100%> (+0.09%)	⬆️
glue/viewers/image/state.py	90.09% <91.42%> (-0.04%)	⬇️
glue/viewers/table/qt/data_viewer.py	96.95% <0%> (+0.09%)	⬆️
glue/viewers/common/qt/data_viewer.py	98.74% <0%> (+1.61%)	⬆️
glue/main.py	93.92% <0%> (+2.15%)	⬆️
glue/_deps.py	66.25% <0%> (+2.45%)	⬆️
glue/core/layer_artist.py	81.21% <0%> (+3.18%)	⬆️
glue/core/hub.py	85.58% <0%> (+7.2%)	⬆️

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