style(spinner): fix positioning for conditional champs

app/assets/stylesheets/forms.scss

@@ -514,7 +514,7 @@
     }
   }
 
-  fieldset ~ .spinner {
+  fieldset + .spinner {
     position: relative;
     top: -($default-fields-spacer / 2);
   }

app/javascript/controllers/autosave_controller.ts

@@ -124,12 +124,12 @@ export class AutosaveController extends ApplicationController {
   private showSpinner(champElement: Element) {
     this.#spinnerTimeoutId = setTimeout(() => {
       // do not do anything if there is already a spinner for this champ, like SIRET champ
-      if (!champElement.querySelector('.spinner')) {
+      if (!champElement.nextElementSibling?.classList.contains('spinner')) {
         const spinner = document.createElement('div');
         spinner.classList.add('spinner', 'spinner-removable');
         spinner.setAttribute('aria-live', 'live');
         spinner.setAttribute('aria-label', 'Chargement en cours…');
-        champElement.appendChild(spinner);
+        champElement.insertAdjacentElement('afterend', spinner);
       }
     }, AUTOSAVE_CONDITIONAL_SPINNER_DEBOUNCE_DELAY);
   }

app/views/shared/dossiers/_update_champs.turbo_stream.haml

@@ -11,8 +11,8 @@
       = turbo_stream.update champ.labelledby_id do
         = render EditableChamp::ChampLabelContentComponent.new champ:, form:
 
-= turbo_stream.remove_all(".editable-champ .spinner-removable")
-= turbo_stream.hide_all(".editable-champ .spinner")
+= turbo_stream.remove_all(".editable-champ + .spinner-removable")
+= turbo_stream.hide_all(".editable-champ + .spinner")
 
 - if dossier.present?
   = turbo_stream.replace_all '.dossier-edit-sticky-footer' do