[Feature Request]: Filter rows - redesign condition builder

### What would you like to happen?

In the **Filter rows** transform (and in other transforms with a condition builder) you can - quite easily - add subconditions in order to make complex expressions, but you can't delete a subcondition if you happen to no longer need it: in this scenario, you can only recreate the transform from scratch.

Proposed solution: add a ⛔ button next to each subcondition that does the task :)

### Issue Priority

Priority: 2

### Issue Component

Component: Hop Gui, Component: Transforms

Start in the Hop Gui Filter rows transform and inspect the condition-builder UI used by transforms. Verify that each added subcondition exposes a delete control and that removing one leaves the remaining expression usable; check any existing GUI or transform tests if present.

Written by the indexing model from the issue text.