fix: paths in gRPC requests and proto state

[ryan-willis]

To test the majority of this, follow the steps in my comment here

Changes:

• Makes proto files de-selectable in the dialog
• Fixes request switching losing method list (closes Only the first package's request is loaded - needs component reload to see other packages #6963)
• Adds path prefix support (closes gRPC calls don't allow for prefixes in request paths #5203, closes Connecting to gRPC server via Azure API Management having suffix in URL #7744)
• Adds user-friendly error messages for common issues (closes gRPC Server Reflection gives error message #6380)
• Switches to using Kong/grpc-reflection-js

[jackkav]

Very thorough work, easy to review too thanks!

Only feedback would be to add any future work or implementation ideas or uncertainties in the pr description for completeness. Eg something you could have done if more time was spent on it but was scoped out