Improve date selection functionality on publicity forms

Update Popover component to be non-modal for date inputs in PublicityForm.tsx.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 1e4433b5-47ab-464c-b663-fea2e53367dd
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/1e4433b5-47ab-464c-b663-fea2e53367dd/zt9Qfys

client/src/components/PublicityForm.tsx

@@ -182,7 +182,7 @@ export default function PublicityForm({ publicity, groups, onSuccess, selectedYe
       <div className="grid grid-cols-2 gap-4">
         <div className="space-y-2">
           <Label>Date de début</Label>
-          <Popover open={startCalendarOpen} onOpenChange={setStartCalendarOpen}>
+          <Popover modal={false} open={startCalendarOpen} onOpenChange={setStartCalendarOpen}>
             <PopoverTrigger asChild>
               <Button
                 variant="outline"
@@ -220,7 +220,7 @@ export default function PublicityForm({ publicity, groups, onSuccess, selectedYe
 
         <div className="space-y-2">
           <Label>Date de fin</Label>
-          <Popover open={endCalendarOpen} onOpenChange={setEndCalendarOpen}>
+          <Popover modal={false} open={endCalendarOpen} onOpenChange={setEndCalendarOpen}>
             <PopoverTrigger asChild>
               <Button
                 variant="outline"