When the host config value for `requestConfigFromFrame` is an object containing a string and a number, it is assumed that the remaining host config is be fetched from the parent frame via RPC. In this context, any other values passed along via the iframe URL hash are ignored. One such value is the `group` which is used by the notebook to focus a group and filter only to that groups annotations.

This changes the method that merges the configs to allow that `group` value to be taken from the iframe's url and incorporated into the final merged config so that the notebook can set that value in its own store.