Enable border on sortableTable by default

Fixes brave#10434
Follow-up to brave#10265

Auditors: @cezaraugusto

Test Plan:
1. Run `npm run add-simulated-synopsis-visits 100`
2. Open about:preferences#payments
3. Pin some sites
4. Make sure the orange border appears on the table

app/renderer/components/common/sortableTable.js

@@ -481,7 +481,10 @@ const styles = StyleSheet.create({
   table: {
     boxSizing: 'border-box',
     cursor: 'default',
-    borderSpacing: 0
+    borderSpacing: 0,
+
+    // #10434: Enable border on the table by default
+    borderCollapse: 'collapse'
   },
 
   // Setting 'fillAvailable' maximizes the width of the table.