Refactor signing publications

[devcrocod]

Add a new function for signing publications

Motivation and Context

In the latest release build, the artifact signing tasks were not included

Breaking Changes

no

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[Copilot]

Pull Request Overview

This PR refactors the publication signing configuration by extracting signing logic into a dedicated function and updating the signing mechanism to use the MavenPublishBaseExtension API.

• Extracts signing configuration into a reusable configureSigning function
• Replaces direct signing API usage with MavenPublishBaseExtension methods
• Removes unnecessary publishing and mavenLocal() repository configuration

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[Copilot]

The order of operations is incorrect. signing.useInMemoryPgpKeys() should be called before mavenPublishing.signAllPublications() to ensure the signing configuration is properly set up before attempting to sign publications.

Suggested change

	mavenPublishing.signAllPublications()
	signing.useInMemoryPgpKeys(signingKey.get(), signingPassphrase.get())
	signing.useInMemoryPgpKeys(signingKey.get(), signingPassphrase.get())
	mavenPublishing.signAllPublications()