fix(widgetoverlay): light mode wrong background color

Signed-off-by: Marcucella, Henry <Henry.Marcucella@fmr.com>

.changeset/yummy-clowns-fetch.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-home': patch
+---
+
+Updated WidgetOverlay color to use `alpha(theme.palette.background.paper, 0.93)` for better theme alignment instead of hardcoded RGBA

plugins/home/src/components/CustomHomepage/WidgetSettingsOverlay.tsx

@@ -21,7 +21,12 @@ import DialogContent from '@material-ui/core/DialogContent';
 import Grid from '@material-ui/core/Grid';
 import IconButton from '@material-ui/core/IconButton';
 import Tooltip from '@material-ui/core/Tooltip';
-import { createStyles, makeStyles, Theme } from '@material-ui/core/styles';
+import {
+  alpha,
+  createStyles,
+  makeStyles,
+  Theme,
+} from '@material-ui/core/styles';
 import DeleteIcon from '@material-ui/icons/Delete';
 import SettingsIcon from '@material-ui/icons/Settings';
 import { useState } from 'react';
@@ -44,7 +49,7 @@ const useStyles = makeStyles((theme: Theme) =>
     },
     settingsOverlay: {
       position: 'absolute',
-      backgroundColor: 'rgba(40, 40, 40, 0.93)',
+      backgroundColor: alpha(theme.palette.background.paper, 0.93),
       width: '100%',
       height: '100%',
       top: 0,