refactor: tweaks to chakra theme config (#824)

apps/client/src/App.tsx

@@ -47,9 +47,8 @@ function App() {
       }
     };
   }, [isElectron, sendToElectron]);
-
   return (
-    <ChakraProvider resetCSS theme={theme}>
+    <ChakraProvider disableGlobalStyle resetCSS theme={theme}>
       <QueryClientProvider client={ontimeQueryClient}>
         <AppContextProvider>
           <BrowserRouter>

apps/client/src/theme/theme.ts

@@ -31,6 +31,8 @@ import {
 import { ontimeTooltip } from './ontimeTooltip';
 
 const theme = extendTheme({
+  initialColorMode: 'dark',
+  useSystemColorMode: false,
   components: {
     Alert: {
       variants: {