The Pad Definition dialog box appears and the application previews a pad with a default dimension value.
In the Type field, set the Type option to Up to surface.
Select the vertical circular face. This face belongs to the same body as the existing pad.
Using the Up to surface option, you can select a face belonging to the same body as the sketch or a face belonging to Part Body.
The face trims the extrusion.
Contextual commands creating the surfaces you need are available from the Limit field: