Always show assign to me button

src/registrar/assets/js/get-gov-admin.js

@@ -169,12 +169,6 @@ function openInNewTab(el, removeAttribute = false){
         }
     });
 
-    // Listen to any change events, and hide the parent container if investigator has a value.
-    selector.on('change', function() {
-        // The parent container has display type flex.
-        assignSelfButton.parentElement.style.display = this.value ? "none" : "flex";
-    });
-
 })();
 /** An IIFE for pages in DjangoAdmin that use a clipboard button
 */

src/registrar/templates/django/admin/includes/detail_table_fieldset.html

@@ -174,7 +174,7 @@ This is using a custom implementation fieldset.html (see admin/fieldset.html)
                 {% endif %}
             </span>
         </div>
-    {% elif field.field.name == "investigator" and not field.is_readonly and not original_object.investigator %}
+    {% elif field.field.name == "investigator" and not field.is_readonly %}
         <div class="flex-container">
             <label aria-label="Assign yourself as the investigator"></label>
             <button id="investigator__assign_self"