Update submit method to have a fallback if the button is not found.

Closes #3426831

js/src/multiselect-dropdowns.js

@@ -172,7 +172,7 @@ export default class MultiselectDropdowns {
    * @return {NodeListOf<Element|HTMLInputElement>}
    */
   static getCheckboxes(multiselect) {
-    return multiselect.querySelectorAll("[type='checkbox']");
+    return multiselect.querySelectorAll('[type="checkbox"]');
   }
 
   /**
@@ -183,7 +183,7 @@ export default class MultiselectDropdowns {
    * @return {NodeListOf<Element|HTMLInputElement>}
    */
   static getCheckboxesChecked(multiselect) {
-    return multiselect.querySelectorAll("[type='checkbox']:checked");
+    return multiselect.querySelectorAll('[type="checkbox"]:checked');
   }
 
   /**
@@ -194,7 +194,7 @@ export default class MultiselectDropdowns {
    * @return {NodeListOf<Element|HTMLInputElement>}
    */
   static getCheckboxesUnchecked(multiselect) {
-    return multiselect.querySelectorAll("[type='checkbox']:not(:checked)");
+    return multiselect.querySelectorAll('[type="checkbox"]:not(:checked)');
   }
 
   /**
@@ -402,12 +402,14 @@ export default class MultiselectDropdowns {
    * @param {HTMLElement} multiselect
    */
   submit(multiselect) {
+    this.close(multiselect);
     const submitButton = multiselect
       .closest('form')
-      .querySelector("[type='submit']");
+      .querySelector('[type="submit"]');
     if (submitButton) {
-      this.close(multiselect);
       submitButton.click();
+    } else {
+      multiselect.closest('form').requestSubmit();
     }
   }
 }