Finalize e2e GraphQL tests

[adzialocha]

Brings back "dead" e2e tests and fixes an issue where using __typename in the query resulted in an empty response.

Closes #330

📋 Checklist

• Add tests that cover your changes
• Add this PR to the Unreleased section in CHANGELOG.md
• Link this PR to any issues it closes
• New files contain a SPDX license header

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.61 🎉

Comparison is base (784a0ef) 89.46% compared to head (6c12410) 90.07%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #342      +/-   ##
==========================================
+ Coverage   89.46%   90.07%   +0.61%     
==========================================
  Files          70       70              
  Lines        5998     6067      +69     
==========================================
+ Hits         5366     5465      +99     
+ Misses        632      602      -30     

Impacted Files	Coverage Δ
aquadoggo/src/db/stores/query.rs	94.37% <ø> (+0.10%)	⬆️
aquadoggo/src/graphql/types/document_fields.rs	91.22% <ø> (+43.85%)	⬆️
aquadoggo/src/graphql/queries/document.rs	100.00% <100.00%> (ø)
aquadoggo/src/graphql/tests.rs	100.00% <100.00%> (ø)
aquadoggo/src/graphql/utils.rs	59.31% <100.00%> (+0.40%)	⬆️
aquadoggo/src/test_utils/node.rs	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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