Add protocol automatically to storeDomain

[frandiox]

Another minor improvement similar to #984 .
This starts adding https:// automatically if missing to storeDomain:

const {storefront} = createStorefrontClient({
   // ...
   privateStorefrontToken: env.PRIVATE_STOREFRONT_API_TOKEN,
-  storeDomain: `https://${env.PUBLIC_STORE_DOMAIN}`,
+  storeDomain: env.PUBLIC_STORE_DOMAIN,
   storefrontId: env.PUBLIC_STOREFRONT_ID,
 });

[wizardlyhel]

Just have a nitpick. Otherwise all good