Follow-up EstimatorReport: checklist instead of loading bar

[MarieS-WiMLDS]

Is your feature request related to a problem? Please describe.

This bar only has 3 states: 0, 50% and 100%. It can be misleading, because it stays very long at 0%.

Describe the solution you'd like

Instead of a bar, do a checklist. What it could look like:

Step 1 is running

Running predictions for training
Waiting before caching predictions for test

Step 1 is over, step 2 is running

✅ Predictions for training cached successfully
Running predictions for training

Step 1 and 2 are over

✅ Predictions for training cached successfully
✅ Predictions for test cached successfully

Describe alternatives you've considered, if relevant

No response

Additional context

In next versions of scikit learn, we should be able to know the progress inside a step, and we might want to replace it by a bar.