fix: correct GitHub URL branch parsing, multi-dot extensions, and request body validation

[Ojas2095]

Summary

Closes #1940
Closes #1987

This PR addresses two validation bugs that caused valid inputs to be rejected:

1. GitHub URL Parsing & Multi-dot Files (#1940)

• The convertGitHubWebUrl regex parser has been simplified to return a raw.githubusercontent.com URL natively handling branches containing slashes (/).
• Replaced fileName.split('.')[1] with path.extname() and parts.pop() in SpecificationFile and file.ts to ensure multi-dot specification files like my.asyncapi.yaml parse securely.

2. Request Body Validation Skip (#1987)

• In validation.middleware.ts, when compileAjv returns undefined (e.g., for routes with no requestBody such as GET/DELETE), we now correctly call next() instead of throwing a misleading 422 ProblemException.

Testing

• Verified raw.githubusercontent.com resolution for deeply nested branch names.
• Tested file creation with multi-dot names.
• Handled missing request bodies gracefully for GET/DELETE methods.
• Automated tests passing successfully.

[changeset-bot]

🦋 Changeset detected

Latest commit: 64cd5fc

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@asyncapi/cli	Patch

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[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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