chore: use ArgumentNullException.ThrowIfNull where applicable

[JamieMagee]

What

Replaces a pre-.NET 6 ?? throw new ArgumentNullException(nameof(x)) pattern with ArgumentNullException.ThrowIfNull(x) (.NET 6+) in PatternMatchingUtility.CompiledMatcher.

The inline ?? throw was nested in a : this(...) constructor chain; it has been hoisted into a small private ToArray helper so the null check uses ArgumentNullException.ThrowIfNull while preserving identical behavior (same exception type, same ParamName).

Sites intentionally not changed

• Custom messages: DotNetComponent and DependencyGraph.AddComponent ("Invalid component node id") pass a descriptive second argument worth keeping.
• IsNullOrWhiteSpace checks: ComponentRecorder.CreateSingleFileComponentRecorder and DependencyGraph.GetExplicitReferencedDependencyIds throw ArgumentNullException for null and empty/whitespace strings, with explicit tests covering all three cases. ArgumentNullException.ThrowIfNull would only handle the null case, so the existing pattern is preserved.
• netstandard2.0 projects: Microsoft.ComponentDetection.Contracts targets netstandard2.0, where ArgumentNullException.ThrowIfNull is unavailable. The sites in NpmAuthor and FileComponentDetectorWithCleanup are left as-is.

Why

ArgumentNullException.ThrowIfNull is the modern, intent-revealing form. It throws the same exception type with the same ParamName, so behavior is identical for callers and tests.

Part 5 of a 6-PR cleanup series removing .NET-Framework-era anachronisms.

[Copilot]

Pull request overview

Updates PatternMatchingUtility.CompiledMatcher to use the .NET 6+ ArgumentNullException.ThrowIfNull pattern while preserving the existing constructor chaining behavior and exception semantics.

Changes:

• Replaces the inline patterns ?? throw ... / .ToArray() expression in the CompiledMatcher(IEnumerable<string>) constructor initializer with a helper method call.
• Adds a private ToArray(IEnumerable<string>) helper that performs ThrowIfNull and converts to string[] efficiently (avoiding enumeration when already an array).

Show a summary per file

File	Description
src/Microsoft.ComponentDetection.Common/PatternMatchingUtility.cs	Introduces a ToArray helper to enable ArgumentNullException.ThrowIfNull in the CompiledMatcher constructor initializer while keeping behavior consistent.

Copilot's findings

• Files reviewed: 1/1 changed files
• Comments generated: 0

[github-actions]

👋 Hi! It looks like you modified some files in the Detectors folder.
You may need to bump the detector versions if any of the following scenarios apply:

• The detector detects more or fewer components than before
• The detector generates different parent/child graph relationships than before
• The detector generates different devDependencies values than before

If none of the above scenarios apply, feel free to ignore this comment 🙂