Restore canvas check to avoid unrelated changes

packages/e2e-test-utils-playwright/src/admin/visit-site-editor.ts

@@ -11,6 +11,8 @@ interface SiteEditorOptions {
 	showWelcomeGuide?: boolean;
 }
 
+const CANVAS_SELECTOR = 'iframe[title="Editor canvas"i] >> visible=true';
+
 /**
  * Visits the Site Editor main page.
  *
@@ -40,7 +42,18 @@ export async function visitSiteEditor(
 		} );
 	}
 
-	// TODO: Ideally the content underneath the canvas loader should be marked inert until it's ready.
+	// Check if the current page has an editor canvas first.
+	if ( ( await this.page.locator( CANVAS_SELECTOR ).count() ) > 0 ) {
+		// The site editor initially loads with an empty body,
+		// we need to wait for the editor canvas to be rendered.
+		await this.page
+			.frameLocator( CANVAS_SELECTOR )
+			.locator( 'body > *' )
+			.first()
+			.waitFor();
+	}
+	// TODO: Ideally the content underneath the canvas loader should be marked
+	// inert until it's ready.
 	await this.page
 		.locator( '.edit-site-canvas-loader' )
 		// Bigger timeout is needed for larger entities, for example the large