Fix the viirs EDR tests for newer xarray

[mraspaud]

This PR fixes the Viirs EDR tests for new xarray.

Dtype checks were failing because of the test file generation was being given float64 scale and offset parameters to the encoding.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.92%. Comparing base (3aa2f79) to head (24109a1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2774   +/-   ##
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  Coverage   95.92%   95.92%           
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  Files         377      377           
  Lines       53535    53535           
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  Hits        51356    51356           
  Misses       2179     2179           

Flag	Coverage Δ
behaviourtests	4.10% <0.00%> (ø)
unittests	96.02% <100.00%> (ø)

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[coveralls]

Pull Request Test Coverage Report for Build 8524637244

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 96.008%

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Totals
Change from base Build 8450068387:	0.0%
Covered Lines:	51228
Relevant Lines:	53358

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💛 - Coveralls

[djhoese]

This makes sense for why this was an issue as the reader uses auto mask and scale from xarray/netcdf4-python:

satpy/satpy/readers/viirs_edr.py

Line 103 in 9952f39

mask_and_scale=True,

Thanks for fixing this.