activities-switch with tab-bar and multiple frames should show all open activities

Currently, ```activities-switch``` with tab-bar-mode and multiple open frames seems to elide activities that are foreign to the current frame. I'd like to be able to switch activities (and raise the relevant) from wherever I am.

Is this a matter of offering the option to suppress this mapping?

```elisp
(define-minor-mode activities-tabs-mode
...
(let ((override-map '((activities-activity-active-p . activities-tabs-activity-active-p)
```