fix stream not available error for simple client.tool call

[Rajesh-Narayanappa87]

Fix for issue - #223

Motivation and Context

• Unable to call client.tool({xx}) using mcp client.
• Code was assuming provided payload is stream. getRawBody() function is failing as req is not stream.
• Now, it will be last condition to be checked.

How Has This Been Tested?

Yes

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

Additional context

This is to fix issue reported #223