Minor UI Fixes (#3108)

* Fix Filter button padding

* Fix sign/verify closing popup

lib/new-ui/widgets/coins_page/assets_history/assets_top_bar.dart

@@ -67,7 +67,7 @@ class AssetsTopBar extends StatelessWidget {
                   child: Padding(
                     padding: const EdgeInsets.symmetric(horizontal: 12.0),
                     child: Row(
-                      spacing: 0,
+                      spacing: 6,
                       children: [
                     CakeImageWidget(
                         imageUrl: "assets/new-ui/options_slider.svg",

lib/src/screens/dashboard/sign_page.dart

@@ -144,13 +144,13 @@ class _SignPageState extends State<SignPage> {
         WidgetsBinding.instance.addPostFrameCallback((_) {
           showPopUp<void>(
               context: context,
-              builder: (_) {
+              builder: (_context) {
                 return AlertWithOneAction(
                   alertTitle: S.current.error,
                   alertContent: state.error,
                   buttonText: S.of(context).ok,
                   buttonAction: () {
-                    if (context.mounted && Navigator.canPop(context)) Navigator.of(context).pop();
+                    if (context.mounted && Navigator.canPop(_context)) Navigator.of(_context).pop();
                   },
                 );
               });