feat: remove site wide perms from creating a workspace (#17296)

Creating a workspace required `read` on site wide `user`. 
Only organization permissions should be required.

coderd/httpapi/noop.go

@@ -0,0 +1,10 @@
+package httpapi
+
+import "net/http"
+
+// NoopResponseWriter is a response writer that does nothing.
+type NoopResponseWriter struct{}
+
+func (NoopResponseWriter) Header() http.Header         { return http.Header{} }
+func (NoopResponseWriter) Write(p []byte) (int, error) { return len(p), nil }
+func (NoopResponseWriter) WriteHeader(int)             {}