Difficult to add field to the bottom of form

[wollefitz]

Describe the Bug

It's very difficult to add fields to the bottom of a form. The cursor needs to be in a small section at the bottom of the form and at the edge of the editor to be able to insert a new field. Can be frustrating at times

Steps to Reproduce

1. Create form
2. Add fields vertically until you get to the bottom
3. Attempt to add more fields and discover how difficult it can be

Expected Behavior

I should be able to scroll past the bottom and add new fields more easily

Environment

• Host (Browser/Node version), if applicable: [e.g. MS Edge 18, Chrome 69, Node 10 LTS]
• OS: [e.g. Windows 7]
• Library version: [e.g. 2.0.0]

[wollefitz]

Transferred from https://github.com/camunda/web-modeler/issues/5505.