Function existsPopupMenuActionById

existsPopupMenuActionById(actionId): boolean
JMap.Application.User.existsPopupMenuActionById

Returns true if an action menu exists for the given id, else false.
Parameters
- actionId: string
  the action menu id
Returns boolean
Throws
if actionId is not a string (non empty)

Example
```
// returns true if the action menu id="my-custom-action-menu" exists, else false
JMap.Application.User.existsPopupMenuActionById("my-custom-action-menu")
```