Simplify PatternMatchingUtility by removing expression trees

[JamieMagee]

Replaces the expression tree and reflection-based implementation in PatternMatchingUtility with plain closures.

The old code used Expression.Lambda, Expression.Call, and four reflection GetMethod lookups to build a compiled delegate at runtime. This was unnecessary given the small, static pattern lists from detector SearchPatterns (typically 1-3 entries). The reflection calls had no null checks and would throw cryptic errors if the API surface changed. Calling Aggregate on an empty pattern list would throw InvalidOperationException.

The new version calls the same ReadOnlySpan<char> extension methods directly from closures. It also handles *foo* (contains) patterns, which the old code silently treated as exact matches.

[Copilot]

Pull request overview

This PR simplifies PatternMatchingUtility by replacing the prior expression-tree/reflection approach with straightforward, prebuilt closures for pattern matching. This reduces runtime complexity and removes failure modes from reflection lookups, while also making empty pattern lists safe to handle.

Changes:

• Replaced expression-tree compiled predicate generation with a list of simple per-pattern match delegates (closures).
• Added support for *foo* “contains” patterns, and ensured empty pattern lists return a matcher that never matches (instead of throwing).
• Consolidated and expanded unit test coverage to cover more pattern variants, multiple-pattern OR behavior, and empty pattern lists.

Show a summary per file

File	Description
src/Microsoft.ComponentDetection.Common/PatternMatchingUtility.cs	Removes expression trees/reflection and implements matching via direct span-based closures (including *foo* contains and empty pattern handling).
test/Microsoft.ComponentDetection.Common.Tests/PatternMatchingUtilityTests.cs	Updates tests to data-drive single-pattern cases, and adds coverage for multi-pattern and empty-pattern behavior.

Copilot's findings

• Files reviewed: 2/2 changed files
• Comments generated: 0 new

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 0.0%. Comparing base (97f3d73) to head (e7b0e8e).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@     Coverage Diff      @@
##   main   #1766   +/-   ##
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[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 🙂