fix: Use a lighter color for dialogs

- Remove unnecessary MuiPaper override
- Add MuiDialog override to specify paper color
- Specify lighter paper color for dialog, to distinguish it from lists popup
- Add dialogPaper entry in Palette

src/theme/custom/cosmoDark/palette.js

@@ -64,6 +64,7 @@ export default {
     paper: themeColors.background,
     secondary: themeColors.backgroundVariant,
     card: themeColors.surface,
+    dialogPaper: themeColors.surface,
     signInPage: themeColors.backgroundSignInPage,
     signInButton: themeColors.backgroundSignInButton
   }

src/theme/overrides/MuiDialog.js

@@ -0,0 +1,10 @@
+// Copyright (c) Cosmo Tech.
+// Licensed under the MIT license.
+
+import { palette } from '../custom';
+
+export default {
+  paper: {
+    backgroundColor: palette.background.dialogPaper
+  }
+};

src/theme/overrides/index.js

@@ -3,8 +3,8 @@
 
 import MuiButton from './MuiButton';
 import MuiCard from './MuiCard';
+import MuiDialog from './MuiDialog';
 import MuiIconButton from './MuiIconButton';
-import MuiPaper from './MuiPaper';
 import MuiTableCell from './MuiTableCell';
 import MuiTableHead from './MuiTableHead';
 import MuiTypography from './MuiTypography';
@@ -13,13 +13,13 @@ import MuiTypography from './MuiTypography';
 export default {
   MuiButton,
   MuiCard,
+  MuiDialog,
   MuiCardHeader: {
     title: {
       fontSize: '14px'
     }
   },
   MuiIconButton,
-  MuiPaper,
   MuiTableCell,
   MuiTableHead,
   MuiTypography