chore: Update experiment status display in Leva experiments view

The commit updates the `_experiment.html.erb` partial in the Leva experiments view. It modifies the status display to show the capitalized status of the experiment if available, and "N/A" if not. This change improves the consistency and clarity of the experiment status information.

Related to recent user commits that updated the top bar in the Leva workbench view, refactored results, improved the dataset, and made enhancements to the workbench and Leva views. Also aligns with recent repository commits that updated navigation styling and links, updated the Leva gem, and updated foreign key references in migration files.

app/views/leva/experiments/_experiment.html.erb

@@ -1,6 +1,6 @@
 <div class="bg-gray-800 rounded-lg shadow-lg p-6">
   <h3 class="text-xl font-semibold mb-2 text-indigo-200"><%= experiment.name %></h3>
-  <p class="text-gray-400 mb-2">Status: <%= experiment.status.capitalize %></p>
+  <p class="text-gray-400 mb-2">Status: <%= experiment.status&.capitalize || 'N/A' %></p>
   <div class="flex space-x-2">
     <%= link_to 'View Results', experiment_path(experiment), class: "btn btn-small btn-primary flex-1 text-center" %>
     <%= link_to 'Edit', edit_experiment_path(experiment), class: "btn btn-small btn-secondary flex-1 text-center" %>