Handle scoped npm packages in `package.get_npm_data_from_purl`

[keshav-space]

Current implementation of get_npm_data_from_purl ignores the namespace of the package.
Instead, we should take into account the namespace for properly handling scoped npm packages.

[SahilKhanWDC]

Hello @keshav-space if someone is not working on this issue then i would like to work on this issue, can u assign this issue to me?