fix(date-picker): remove modal prop to prevent focus trap conflict (CCExtractor#280)

- Removed modal={true} from Popover component in date-picker.tsx.
- Prevents nested focus trap conflict.
- Fixes page becoming unresponsive after clicking outside date picker.

Fixes: CCExtractor#279

Author: ShivaGupta-14

frontend/src/components/ui/date-picker.tsx

@@ -23,7 +23,7 @@ export function DatePicker({
   className,
 }: DatePickerProps) {
   return (
-    <Popover modal={true}>
+    <Popover>
       <PopoverTrigger asChild>
         <Button
           variant={'outline'}