Removes switching on read / write permissions for FB login

SDK 5+ no longer differentiates between read / write permissions as of facebook/facebook-ios-sdk@6c4ac12

Author: drdaz

ParseFacebookUtils/ParseFacebookUtils/Internal/AuthenticationProvider/iOS/PFFacebookMobileAuthenticationProvider.m

@@ -43,13 +43,8 @@ - (instancetype)initWithApplication:(UIApplication *)application
 - (BFTask<NSDictionary<NSString *, NSString *>*> *)authenticateAsyncWithReadPermissions:(nullable NSArray<NSString *> *)readPermissions
                                                                      publishPermissions:(nullable NSArray<NSString *> *)publishPermissions
                                                                      fromViewComtroller:(UIViewController *)viewController {
-    if (readPermissions && publishPermissions) {
-        NSString *description = @"Read permissions are not permitted to be requested with publish permissions.";
-        NSError *error = [NSError errorWithDomain:PFParseErrorDomain
-                                             code:kPFErrorFacebookInvalidSession
-                                         userInfo:@{ NSLocalizedDescriptionKey: description }];
-        return [BFTask taskWithError:error];
-    }
+    
+    NSArray *permissions = [readPermissions arrayByAddingObjectsFromArray:publishPermissions];
 
     BFTaskCompletionSource *taskCompletionSource = [BFTaskCompletionSource taskCompletionSource];
     FBSDKLoginManagerLoginResultBlock resultHandler = ^(FBSDKLoginManagerLoginResult *result, NSError *error) {
@@ -61,12 +56,9 @@ - (instancetype)initWithApplication:(UIApplication *)application
             taskCompletionSource.result = [PFFacebookPrivateUtilities userAuthenticationDataFromAccessToken:result.token];
         }
     };
-                                                                       
-    if (publishPermissions) {
-        [self.loginManager logInWithPermissions:publishPermissions fromViewController:viewController handler:resultHandler];
-    } else {
-        [self.loginManager logInWithPermissions:readPermissions fromViewController:viewController handler:resultHandler];
-    }
+    
+    [self.loginManager logInWithPermissions:permissions fromViewController:viewController handler:resultHandler];
+    
     return taskCompletionSource.task;
 }