Refactor collection initializers to use C# 12 collection expressions

This commit updates various files across the Core and WebApp projects to replace traditional collection initializers with C# 12 collection expressions. Changes include modifications to EventAssignment.cs, TeamScheduler_DecisionTree.cs, CareerField.cs, EventDefinition.cs, and several components in the WebApp. These updates enhance code readability and maintainability by adhering to modern C# syntax standards.

WebApp/Components/Features/MeetingSchedule/Index.razor

@@ -178,7 +178,7 @@
             _scheduledTeams = _scheduledTeams.Where(t => t != unassignedTeam);
         else
         {
-            _scheduledTeams = _scheduledTeams.Concat(new[] { unassignedTeam });
+            _scheduledTeams = _scheduledTeams.Concat([unassignedTeam]);
         }
         await SaveScheduledTeams();
     }
@@ -216,6 +216,7 @@
 
         _teams
             = await Context.Teams
+                .AsNoTracking()
                 .Include(e => e.Event)
                 .Include(e => e.Students)
                 .OrderBy(e => e.Event.Name)
@@ -224,6 +225,7 @@
 
         _students =
             await Context.Students
+                .AsNoTracking()
                 .Include(e => e.Teams)
                 .ThenInclude(e => e.Captain)
                 .Include(e => e.EventRankings)
@@ -311,13 +313,13 @@
 
         // Try recommendation strategies in priority order
         var scheduler = new UnassignedStudentScheduler(_teams, _solution.TimeSlots);
-        var strategies = new[]
-        {
+        UnassignedScheduleStrategy[] strategies =
+        [
             UnassignedScheduleStrategy.LevelOfEffort,
             UnassignedScheduleStrategy.BiggestGroup,
             UnassignedScheduleStrategy.AnyNotMeetingAlready,
             UnassignedScheduleStrategy.IndividualEvents
-        };
+        ];
 
         _possibleAdditions = strategies
             .Select(strategy => scheduler.ScheduleStrategy(strategy))