Don't add '/' when building the full url from base and page.

@@ -31,8 +31,8 @@ const baseQuery = fetchBaseQuery()
 
 const siteBaseQuery = async (args, api, options) => {
   const { site, url } = args
-  const baseUrl = getSiteBaseUrl(site)
-  return baseQuery({ ...args, url: `${baseUrl ? `${baseUrl}/` : ''}${url}` }, api, options)
+  const baseUrl = getSiteBaseUrl(site) || ''
+  return baseQuery({ ...args, url: `${baseUrl}${url}` }, api, options)
 }
 
 export const sitePageSlice = createApi({
@@ -80,7 +80,7 @@ export const getUrl = async(url: string) => {
   for (const site of sites) {
     const baseUrl = configSlice.selectors.getSiteBaseUrl(state, site)
     if (url.startsWith(baseUrl)) {
-      return getSitePage(site, url.substring(baseUrl.length + 1))
+      return getSitePage(site, url.substring(baseUrl.length))
     }
   }
   return getSitePage('default', url)