fix: Remove null type cast in `receipt_remote_data_source.dart`

[marfavi]

Closes #426

[ghost]

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#### [](https://app.codesee.io/r/reviews?pr=479&src=https%3A%2F%2Fgithub.com%2FAnalogIO%2Fcoffeecard_app) #### Legend

[codecov[bot]]

Codecov Report

Merging #479 (067586e) into develop (82c5bc3) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #479   +/-   ##
========================================
  Coverage    67.76%   67.76%           
========================================
  Files          101      101           
  Lines         1123     1120    -3     
========================================
- Hits           761      759    -2     
+ Misses         362      361    -1     

Flag	Coverage Δ
unittests	67.76% <100.00%> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...t/data/datasources/receipt_remote_data_source.dart	90.00% <100.00%> (+5.38%)	:arrow_up:

[fremartini]

has this been fixed in the backend?

[marfavi]

has this been fixed in the backend?

Yes, https://github.com/AnalogIO/coffeecard_app/issues/426#issuecomment-1546760135