ProcedureKind is `Query` for mutations

[banool]

Imagine some middleware like this:

let block_viewer_mutations = |mw: MiddlewareBuilder<AuthenticatedRspcContext>| {
    mw.middleware(
        |mw: MiddlewareContext<AuthenticatedRspcContext>| async move {
            if let Some(org_ctx) = &mw.ctx.organization_context {
                if org_ctx.organization_role == OrganizationRole::Viewer
                    && matches!(mw.req.kind, rspc::internal::ProcedureKind::Mutation)
                {
                    return Err(Into::into(ApiGatewayError::Unauthorized(
                        "Viewers are not allowed to perform mutations".into(),
                    )));
                }
            }
            Ok(mw)
        },
    )
};

This doesn't actually work because even on mutations, mw.req.kind is Query. This error is present at least as of commit fe991f0, though I can't see any issues or PRs that mention kind since then.

[banool]

I have a fix on our branch here: aptos-labs#2.