Use null-conditional assignment

[glen-84]

Summary of the changes (Less than 80 chars)

• Use null-conditional assignment.

[Copilot]

Pull request overview

This PR applies null-propagation / null-conditional assignment patterns across multiple projects (HotChocolate, Fusion, StrawberryShake, Mocha, GreenDonut) and enables the corresponding ReSharper highlighting to encourage the style consistently.

Changes:

• Replaced explicit null checks/early-returns with null-propagation (?., ??) and null-conditional assignment patterns.
• Simplified several small helper methods and disposal/enrichment blocks by using conditional access chaining.
• Enabled resharper_use_null_propagation_highlighting = warning in .editorconfig and added a targeted suppression comment where needed.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/StrawberryShake/Client/src/Transport.Http/HttpConnection.cs	Uses null-conditional assignment when writing into an optional copy dictionary.
src/Mocha/src/Mocha/Instrumentation/ActivityMessagingDiagnosticListener.cs	Simplifies activity enrichment blocks using conditional access chaining.
src/HotChocolate/Fusion/src/Fusion.Utilities/Rewriters/DocumentRewriter.cs	Uses null-propagation when removing references from an optional dictionary.
src/HotChocolate/Fusion/src/Fusion.Execution/Planning/Partitioners/SelectionSetPartitioner.cs	Collapses a null-check + return into a single null-propagating query.
src/HotChocolate/Fusion/src/Fusion.Execution/Execution/Nodes/OperationExecutionNode.cs	Simplifies disposal of singleResult with conditional access.
src/HotChocolate/Core/test/Types.Tests/SchemaBuilderTests.cs	Uses null-conditional assignment when mutating optional configuration in a test.
src/HotChocolate/Core/src/Types/Types/Directive.cs	Uses null-conditional assignment for optional rewritten-argument buffer.
src/HotChocolate/Core/src/Types/Types/Descriptors/Conventions/DescriptorContext.Services.cs	Simplifies GetService<T> fallback behavior with ??.
src/HotChocolate/Core/src/Types/Execution/Processing/VariableRewriter.cs	Uses null-conditional assignment when populating optional rewritten buffers.
src/HotChocolate/Core/src/Types/Configuration/AggregateTypeInterceptor.cs	Uses null-conditional assignment when appending into optional temp array.
src/HotChocolate/Core/src/Types.Analyzers/WrongAuthorizationAttributeCodeFixProvider.cs	Adds a targeted ReSharper suppression comment for a known issue.
src/HotChocolate/Core/src/Types.Analyzers/NodeResolverIdParameterCodeFixProvider.cs	Removes an early-return in favor of null-propagation when locating nodes.
src/HotChocolate/Core/src/Types.Analyzers/IdAttributeOnRecordParameterCodeFixProvider.cs	Removes an early-return in favor of null-propagation when locating nodes.
src/HotChocolate/Core/src/Types.Analyzers/Helpers/SymbolExtensions.cs	Uses null-propagation to return null when type symbol resolution fails.
src/HotChocolate/Core/src/Types.Analyzers/Helpers/GeneratorUtils.cs	Uses null-propagation to return null for string escaping when input is null.
src/HotChocolate/Core/src/Abstractions/ExtensionData.cs	Simplifies CopyTo with nullable interface cast + conditional call.
src/HotChocolate/ApolloFederation/test/ApolloFederation.Tests/TestHelper.cs	Uses ?.Invoke for optional mock setup callback.
src/GreenDonut/src/GreenDonut.Data.EntityFramework/Extensions/PagingQueryableExtensions.cs	Uses null-conditional assignment when clearing an optional interceptor holder.
.editorconfig	Enables ReSharper null-propagation highlighting as a warning.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.00%. Comparing base (6e858eb) to head (967a184).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #9561   +/-   ##
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