Fix github.label.description type to nullish

[ikeryo1182]

Description

GitHub's label.description can be null in some cases. While it's marked as "Optional" in the user interface, in API responses it could be null. Since it's described as optional, it might also be undefined, so treating it as nullish would be appropriate.

The fact that it becomes null is probably due to historical reasons, but I don't know the specific details.

Server Details

• Server:
• Changes to:

Motivation and Context

When I executed the search_issue API in my Claude Desktop, the converter encountered an error because the label's description was null.

How Has This Been Tested?

I cloned the repository and set up a server locally to verify the issue.
However, unfortunately, label.description does not become null when you create a new label. It's possible that labels created in the past or through some other route may have null values.

Breaking Changes

Nothing

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 Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

[olaservo]

Hi, this redundant PR was just merged: #694 so I'm closing this one.