Small light theme fixes (#1248)

* Use grey border instead of black shadow in light mode below filter-bar

* Fix some theme colors not updating when theme is changed in real-time

src/renderer/app.tsx

@@ -189,7 +189,7 @@ export const App = () => {
     }, [language]);
 
     return (
-        <MantineProvider defaultColorScheme={mode as 'dark' | 'light'} theme={theme}>
+        <MantineProvider forceColorScheme={mode} theme={theme}>
             <Notifications
                 containerWidth="300px"
                 position="bottom-center"

src/renderer/features/shared/components/filter-bar.module.css

@@ -1,5 +1,12 @@
 .filter-bar {
     z-index: 1;
     padding: var(--theme-spacing-md) var(--theme-spacing-sm);
-    box-shadow: 0 5px 15px rgb(0 0 0 / 65%);
+
+    @mixin dark {
+        box-shadow: 0 5px 15px rgb(0 0 0 / 65%);
+    }
+
+    @mixin light {
+        box-shadow: 0 2px 0 var(--theme-colors-border);
+    }
 }