fix(create-vite): fix h1 css selector in lit templates (#12951)

Author: danieldeandradelopes

packages/create-vite/template-lit-ts/src/my-element.ts

@@ -76,7 +76,7 @@ export class MyElement extends LitElement {
       color: #888;
     }
 
-    h1 {
+    ::slotted(h1) {
       font-size: 3.2em;
       line-height: 1.1;
     }

packages/create-vite/template-lit/src/my-element.js

@@ -92,7 +92,7 @@ export class MyElement extends LitElement {
         color: #535bf2;
       }
 
-      h1 {
+      ::slotted(h1) {
         font-size: 3.2em;
         line-height: 1.1;
       }