Network Login: Cosmetic: Use modern objective-c syntax

Sources/LocalNetworkConnectivity/VLCNetworkLoginDataSourceProtocol.m

@@ -97,7 +97,7 @@ static NSString *const VLCNetworkLoginDataSourceProtocolCellIdentifier = @"VLCNe
 
             // Always use black since the background is always white.
             [self.segmentedControl setTitleTextAttributes:@{NSForegroundColorAttributeName:
-                                                                [UIColor blackColor]}
+                                                                UIColor.blackColor}
                                                  forState:UIControlStateSelected];
         }
         [self.contentView addSubview:_segmentedControl];

Sources/LocalNetworkConnectivity/VLCNetworkLoginViewButtonCell.m

@@ -24,8 +24,8 @@ NSString * const kVLCNetworkLoginViewButtonCellIdentifier = @"VLCNetworkLoginVie
     if (self) {
         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(themeDidChange) name:kVLCThemeDidChangeNotification object:nil];
         [self themeDidChange];
-        self.textLabel.backgroundColor = [UIColor clearColor];
-        self.textLabel.textColor = [UIColor whiteColor];
+        self.textLabel.backgroundColor = UIColor.clearColor;
+        self.textLabel.textColor = UIColor.whiteColor;
         self.textLabel.textAlignment = NSTextAlignmentCenter;
         self.accessibilityTraits = UIAccessibilityTraitButton;