Is your feature request related to a problem? Please describe the problem.

Add the specVersion to generatePluginResult to avoid calling GetKiotaTree twice especially for a large spec file which will be expensive.
Related to #6461
Request from TTK team which uses external OAS and relies on Kiota extension package to know the generated spec file.
Usecase: cases where the generated spec file is upgraded from the initial user's spec input file.

Client library/SDK language

Csharp

Describe the solution you'd like

Add the specVersion to generatePlugin Command so as to pass this to generatePluginResult of the Kiota extension NPM package

Additional context

No response