[MSBUILD SDK] Collect extension files into .azurefunctions output folder

[jviau]

Issue describing the changes in this PR

resolves #3134

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

Additional information

This PR adds msbuild targets to collect the extension bundle files from the generated project. A major difference from the current SDK is that we no longer fully build the generated project, we just collect extension files and then directly copy them to .azurefunctions output folder. This saves us many redundant files copying and cuts down on build time.

[Copilot]

Pull request overview

This PR implements collection of extension bundle files from a generated project and copies them directly to the .azurefunctions output folder, eliminating the need to fully build the generated project. This optimization reduces redundant file copying and improves build performance.

Key changes:

• Added MSBuild targets to collect extension files and copy them to .azurefunctions folder
• Implemented filtering logic to exclude runtime assemblies/packages from the extensions payload
• Added comprehensive test coverage for extension file collection scenarios

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/Azure.Functions.Sdk.Tests/Integration/SdkEndToEndTests.Targets.WorkerConfig.cs	Removed extraneous blank line
test/Azure.Functions.Sdk.Tests/Integration/SdkEndToEndTests.Targets.GetFunctionsExtensionFiles.cs	Added tests for the GetFunctionsExtensionFiles target with and without package references
test/Azure.Functions.Sdk.Tests/Integration/SdkEndToEndTests.Build.cs	Added tests for building with extensions and validation of extensions payload
test/Azure.Functions.Sdk.Tests/Assertions/TaskItemAssertions.cs	Added HaveMetadataLike assertion method for pattern matching metadata values
src/Azure.Functions.Sdk/Tasks/Inner/ResolveExtensionCopyLocal.cs	Implemented task to resolve and filter extension assemblies for the payload
src/Azure.Functions.Sdk/TaskItemExtensions.cs	Added NuGetPackageId property and TryGetNuGetPackageId method
src/Azure.Functions.Sdk/Targets/Inner/Azure.Functions.Sdk.Inner.targets	Added ResolveFunctionsExtensionFiles target and ResolveExtensionCopyLocal task
src/Azure.Functions.Sdk/Targets/Inner/Azure.Functions.Sdk.Inner.props	Added import for runtime packages properties file
src/Azure.Functions.Sdk/Targets/Inner/Azure.Functions.Sdk.Inner.RuntimePackages.props	Defined runtime assemblies and packages to exclude from extensions payload
src/Azure.Functions.Sdk/Targets/Extensions/Azure.Functions.Sdk.Extensions.targets	Added targets to prepare and publish extension payload, and GetFunctionsExtensionFiles target

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