Pre-filled email address input in post preview modal for current user

no issue

- when viewing the email preview in the post preview modal having your email address pre-filled makes sending yourself an email preview much quicker as there's no need to type anything

ghost/admin/app/components/modal-post-preview/email.hbs

@@ -12,7 +12,7 @@
 <div class="gh-post-preview-email-footer">
     <span class="mr3 nowrap fw6 f8 darkgrey">Send a test newsletter</span>
 
-    <div class="gh-post-preview-email-input {{if this.sendPreviewEmailError "error"}}">
+    <div class="gh-post-preview-email-input {{if this.sendPreviewEmailError "error"}}" {{did-insert this.initPreviewEmailAddress}}>
         <Input
             @value={{this.previewEmailAddress}}
             class="gh-input gh-post-preview-email-input"

ghost/admin/app/components/modal-post-preview/email.js

@@ -23,6 +23,7 @@ export default class ModalPostPreviewEmailComponent extends Component {
     @service ajax;
     @service config;
     @service ghostPaths;
+    @service session;
     @service settings;
 
     @tracked html = '';
@@ -48,6 +49,12 @@ export default class ModalPostPreviewEmailComponent extends Component {
         }
     }
 
+    @action
+    async initPreviewEmailAddress() {
+        const user = await this.session.user;
+        this.previewEmailAddress = user.email;
+    }
+
     @task({drop: true})
     *sendPreviewEmailTask() {
         try {