Can I use a pull-cord switch with a Fibaro Universal Dimmer to dim a light?
Yes, this is perfectly possible.
You will need to acquire a "Momentary" pull-cord switch, these are typically used for "alarm" notification purposes in disabled toilets:
The red cord can be replaced with a normal white one if required.
Depending on the size of the pull-cord switch that you obtain, the Fibaro module may not fit inside, so it will need to be installed either at the light fitting itself (likely in the ceiling space) or in a separate enclosure near to the pull-cord switch.
The Fibaro dimmer module will need to be configured to work with a momentary switch - the links to the guides below will help you to do this.