FIX: Disable the post submit button during image processing properly (#13765)

There was a UI bug when submitting multiple files in the same batch. We
would remove the disabled status of the submit button after the previous
file was sucesfully uploaded and the next one was still mid
optimization.

Reported at https://meta.discourse.org/t/-/194841/15?u=falco

app/assets/javascripts/discourse/app/components/composer-editor.js

@@ -652,7 +652,6 @@ export default Component.extend({
         this.setProperties({
           uploadProgress: 0,
           isUploading: false,
-          isProcessingUpload: false,
           isCancellable: false,
         });
       }
@@ -683,6 +682,14 @@ export default Component.extend({
     });
 
     $element
+      .on("fileuploadprocessstart", () => {
+        this.setProperties({
+          uploadProgress: 0,
+          isUploading: true,
+          isProcessingUpload: true,
+          isCancellable: false,
+        });
+      })
       .on("fileuploadprocess", (e, data) => {
         this.appEvents.trigger(
           "composer:insert-text",
@@ -690,12 +697,6 @@ export default Component.extend({
             filename: data.files[data.index].name,
           })}]()\n`
         );
-        this.setProperties({
-          uploadProgress: 0,
-          isUploading: true,
-          isProcessingUpload: true,
-          isCancellable: false,
-        });
       })
       .on("fileuploadprocessalways", (e, data) => {
         this.appEvents.trigger(
@@ -705,6 +706,8 @@ export default Component.extend({
           })}]()\n`,
           ""
         );
+      })
+      .on("fileuploadprocessstop", () => {
         this.setProperties({
           uploadProgress: 0,
           isUploading: false,

app/assets/javascripts/discourse/app/controllers/composer.js

@@ -663,7 +663,7 @@ export default Controller.extend({
     },
   },
 
-  disableSubmit: or("model.loading", "isUploading"),
+  disableSubmit: or("model.loading", "isUploading", "isProcessingUpload"),
 
   save(force, options = {}) {
     if (this.disableSubmit) {

app/assets/javascripts/discourse/app/templates/composer.hbs

@@ -167,7 +167,7 @@
               {{/if}}
             {{/if}}
 
-            {{#if isUploading}}
+            {{#if (or isUploading isProcessingUpload)}}
               <div id="file-uploading">
                 {{#if isProcessingUpload}}
                   {{loading-spinner size="small"}}<span>{{i18n "upload_selector.processing"}}</span>