[Glitch] Rename JSX files with proper .jsx extension

Port 44a7d87cb1 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/features/ui/components/modal_loading.jsx

@@ -0,0 +1,20 @@
+import React from 'react';
+
+import LoadingIndicator from 'flavours/glitch/components/loading_indicator';
+
+// Keep the markup in sync with <BundleModalError />
+// (make sure they have the same dimensions)
+const ModalLoading = () => (
+  <div className='modal-root__modal error-modal'>
+    <div className='error-modal__body'>
+      <LoadingIndicator />
+    </div>
+    <div className='error-modal__footer'>
+      <div>
+        <button className='error-modal__nav onboarding-modal__skip' />
+      </div>
+    </div>
+  </div>
+);
+
+export default ModalLoading;