fix: improve date handling in task addition

The time in addtask was being stored as UTC Time and datepicker using it as datetime(local) which was letting date to go in past.
Which occured assertion error when date picker was being shown again. because date was in past and first date was todays.

Author: SGI-CAPP-AT2

lib/app/modules/home/views/add_task_bottom_sheet.dart

@@ -250,7 +250,7 @@ class AddTaskBottomSheet extends StatelessWidget {
                     },
                     fieldHintText: "Month/Date/Year",
                     context: context,
-                    initialDate: homeController.due.value ?? DateTime.now(),
+                    initialDate: homeController.due.value?? DateTime.now(),
                     firstDate: DateTime.now(),
                     lastDate: DateTime(2037, 12, 31),
                   );
@@ -305,7 +305,7 @@ class AddTaskBottomSheet extends StatelessWidget {
                         ),
                       );
                       // print(dateTime);
-                      homeController.due.value = dateTime.toUtc();
+                      homeController.due.value = dateTime;
 
                       // print("due value ${homeController.due}");
                       homeController.dueString.value =
@@ -442,10 +442,31 @@ class AddTaskBottomSheet extends StatelessWidget {
       ),
       onPressed: () async {
         // print(homeController.formKey.currentState);
+        if(homeController.due.value!=null&&DateTime.now().isAfter(homeController.due.value!)){
+          ScaffoldMessenger.of(context).showSnackBar(SnackBar(
+              content: Text(
+                SentenceManager(
+                    currentLanguage:
+                    homeController.selectedLanguage.value)
+                    .sentences
+                    .addTaskTimeInPast,
+                style: TextStyle(
+                  color: AppSettings.isDarkMode
+                      ? TaskWarriorColors.kprimaryTextColor
+                      : TaskWarriorColors.kLightPrimaryTextColor,
+                ),
+              ),
+              backgroundColor: AppSettings.isDarkMode
+                  ? TaskWarriorColors.ksecondaryBackgroundColor
+                  : TaskWarriorColors
+                  .kLightSecondaryBackgroundColor,
+              duration: const Duration(seconds: 2)));
+          return;
+        }
         if (homeController.formKey.currentState!.validate()) {
           try {
             var task = taskParser(homeController.namecontroller.text)
-                .rebuild((b) => b..due = homeController.due.value)
+                .rebuild((b) => b..due = homeController.due.value?.toUtc())
                 .rebuild((p) => p..priority = homeController.priority.value);
             if (homeController.tagcontroller.text != "") {
               homeController.tags.add(homeController.tagcontroller.text.trim());
@@ -462,6 +483,7 @@ class AddTaskBottomSheet extends StatelessWidget {
             homeController.priority.value = 'M';
             homeController.tagcontroller.text = '';
             homeController.tags.value = [];
+            homeController.due.value=null;
             homeController.update();
             // Navigator.of(context).pop();
             Get.back();