🐛 Fixed post feature image caption updates saving with every keystroke (#18833)

closes TryGhost/Product#4093
- added proper on blur handling to trigger autosave instead of each update to the caption text

ghost/admin/app/components/gh-editor-feature-image.hbs

@@ -75,7 +75,7 @@
                         @onChangeHtml={{this.setCaption}}
                         @placeholderText={{if this.captionInputFocused "" "Add a caption to the feature image"}}
                         @onFocus={{fn (mut this.captionInputFocused) true}}
-                        @onBlur={{fn (mut this.captionInputFocused) false}}
+                        @onBlur={{this.handleCaptionBlur}}
                     />
                 {{/if}}
                 <button

ghost/admin/app/components/gh-editor-feature-image.js

@@ -39,6 +39,12 @@ export default class GhEditorFeatureImageComponent extends Component {
         this.args.updateCaption(cleanedHtml);
     }
 
+    @action
+    handleCaptionBlur() {
+        this.captionInputFocused = false;
+        this.args.handleCaptionBlur();
+    }
+
     @action
     setUploadedImage(results) {
         if (results[0]) {

ghost/admin/app/components/gh-koenig-editor-lexical.hbs

@@ -16,6 +16,7 @@
             @updateAlt={{@setFeatureImageAlt}}
             @caption={{@featureImageCaption}}
             @updateCaption={{@setFeatureImageCaption}}
+            @handleCaptionBlur={{@handleFeatureImageCaptionBlur}}
             @forceButtonDisplay={{or (not @title) (eq @title "(Untitled)") this.titleIsHovered this.titleIsFocused}}
             @isHidden={{or (not @cardOptions.post.showTitleAndFeatureImage) false}}
         />

ghost/admin/app/controllers/lexical-editor.js

@@ -347,7 +347,10 @@ export default class LexicalEditorController extends Controller {
     @action
     setFeatureImageCaption(html) {
         this.post.set('featureImageCaption', html);
+    }
 
+    @action
+    handleFeatureImageCaptionBlur() {
         if (this.post.isDraft) {
             this.autosaveTask.perform();
         }

ghost/admin/app/templates/lexical-editor.hbs

@@ -82,6 +82,7 @@
                 @setFeatureImage={{this.setFeatureImage}}
                 @setFeatureImageAlt={{this.setFeatureImageAlt}}
                 @setFeatureImageCaption={{this.setFeatureImageCaption}}
+                @handleFeatureImageCaptionBlur={{this.handleFeatureImageCaptionBlur}}
                 @clearFeatureImage={{this.clearFeatureImage}}
                 @cardOptions={{hash
                     post=this.post