Removes hardcoded path to svg

What does this MR do and why?

Path to empty state was hardcoded, and is leading to 404 (eg https://gitlab.com/gitlab-org/gitlab/-/ml/experiments). This is being fixed by passing the image path from the backend.

How to set up and validate locally

Reproducing is weird since the old version still works in local branch, it only breaks in production. So at best we can test that it continues working:

1. Enable the feature flag

   echo "Feature.enable(:ml_experiment_tracking)" | bundle exec rails c

2. Go to a project, click on 'Package & Registries > Model Experiments'. Verify that the svg for the empty state is loading.

3. Create an experiment:

   user_id = 1 # if you are using root
   project_id = 20 # not necessarily 20, but the project you are using for testing
   exp = Ml::Experiment.create!(name: 'Gitlab Experiment', user_id: user_id, project_id: project_id)

4. Refresh Model experiments page, and click on the experiment. Verify that the empty svg is loaded on this page as well

MR acceptance checklist

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