fix: download model wrong event emission

[louis-jan]

Describe Your Changes

There was a legacy issue where we combined abort download event and progress event into 1 pipeline.

Download: +------A1-------A2--------A3---X
Cancel : +---B1-----B2-------B3---------X

Problems:

1. We use a throttle without trailing event emission.

• At X, there is no A3 event emitted (e.g., 100% or success event).

2. We add a trailing event emission.

• At A2, we abort the download process -> a B1 event is emitted, then A2 once (aborted -> downloading).

Fixes Issues

• Closes #

Self Checklist

• Added relevant comments, esp in complex areas
• Updated docs (for bug fixes / features)
• Created issues for follow-up changes or refactoring needed