If the fetch has been remapped, and there would be duplicated '/' when

joining the strings, then remove the extra slashes.

@@ -45,7 +45,13 @@ const baseQuery = fetchBaseQuery()
 const siteBaseQuery = async (args, api, options) => {
   const { site, url } = args
   const fetchUrl = getSiteFetchUrl(site) || ''
-  return baseQuery({ ...args, url: `${fetchUrl}${url}` }, api, options)
+  let newUrl
+  if (fetchUrl.endsWith('/') && url.startsWith('/')) {
+    newUrl = fetchUrl + url.replace(/^\/+/, '')
+  } else {
+    newUrl = fetchUrl + url
+  }
+  return baseQuery({ ...args, url: newUrl }, api, options)
 }
 
 export const sitePageSlice = createApi({