fix: isBrowser to include typeof window !== 'undefined' check

There are several checks in GoTrueClient.ts that check window?.[prop] after checking isBrowser() which throws an error in node environments that have "document" defined but not "window". So this is the most minimal check to  be sure they don't throw by ensuring "window" is defined.

src/GoTrueClient.ts

@@ -1524,9 +1524,13 @@ export default class GoTrueClient {
    * Checks if the current URL contains parameters given by an implicit oauth grant flow (https://www.rfc-editor.org/rfc/rfc6749.html#section-4.2)
    */
   private _isImplicitGrantFlow(): boolean {
+    if (!isBrowser()) {
+      return false
+    }
+
     const params = parseParametersFromURL(window.location.href)
 
-    return !!(isBrowser() && (params.access_token || params.error_description))
+    return !!(params.access_token || params.error_description)
   }
 
   /**

src/lib/helpers.ts

@@ -14,7 +14,8 @@ export function uuid() {
   })
 }
 
-export const isBrowser = () => typeof document !== 'undefined'
+export const isBrowser = () =>
+  typeof window !== 'undefined' && typeof document !== 'undefined'
 
 const localStorageWriteTests = {
   tested: false,