feat(nimbus): Add tooltips to new experiment timeline

Because
- The new UI is missing the tooltips on the timeline

This commit
- Adds tooltips to the new experiment timeline explaining what each count of days on the timeline means

Fixes #11748

experimenter/experimenter/nimbus_ui_new/templates/nimbus_experiments/experiment_base.html

@@ -33,7 +33,7 @@ <h4 class="mb-0">{{ experiment.name }}</h4>
                 <small class="mr-2">{{ status.days }} day{{ status.days|pluralize }}</small>
                 <i class="fa-regular fa-circle-question fa-sm ps-1"
                    data-bs-toggle="tooltip"
-                   data-bs-placement="top"
+                   data-bs-placement="bottom"
                    title="{{ status.tooltip }}"></i>
               </div>
             {% endif %}