Fix async await anti-pattern causing lint error

Author: camd

ui/shared/auth/AuthService.js

@@ -12,29 +12,26 @@ export default class AuthService {
     this.setUser = setUser;
   }
 
-  _fetchUser(userSession) {
+  async _fetchUser(userSession) {
     const loginUrl = getApiUrl('/auth/login/');
 
-    // eslint-disable-next-line no-async-promise-executor
-    return new Promise(async (resolve, reject) => {
-      const userResponse = await fetch(loginUrl, {
-        headers: {
-          Authorization: `Bearer ${userSession.accessToken}`,
-          'Access-Token-Expires-At': userSession.accessTokenExpiresAt,
-          'Id-Token': userSession.idToken,
-        },
-        method: 'GET',
-        credentials: 'same-origin',
-      });
-
-      const user = await userResponse.json();
-
-      if (!userResponse.ok) {
-        reject(new Error(user.detail || userResponse.statusText));
-      }
-
-      resolve(new UserModel(user));
+    const userResponse = await fetch(loginUrl, {
+      headers: {
+        Authorization: `Bearer ${userSession.accessToken}`,
+        'Access-Token-Expires-At': userSession.accessTokenExpiresAt,
+        'Id-Token': userSession.idToken,
+      },
+      method: 'GET',
+      credentials: 'same-origin',
     });
+
+    const user = await userResponse.json();
+
+    if (!userResponse.ok) {
+      throw new Error(user.detail || userResponse.statusText);
+    }
+
+    return new UserModel(user);
   }
 
   _clearRenewalTimer() {