test: Isolate network calls in RelationTests and UserTests - #428

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/cache@v4, actions/checkout@v4, actions/setup-dotnet@v4, codecov/codecov-action@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

The variable 'ex' is declared but never used

'Uri.EscapeUriString(string)' is obsolete: 'Uri.EscapeUriString can corrupt the Uri string in some cases. Consider using Uri.EscapeDataString for query string components instead.' (https://aka.ms/dotnet-warnings/SYSLIB0013)

The variable 'ex' is declared but never used

The variable 'ex' is declared but never used

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.

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XML comment has badly formed XML -- 'End tag 'summary' does not match the start tag 'pre'.'