Hi, on this line I have this error:

SVMXC__Timesheet_Entry__c relatedTimeEntry = [Select ID, SVMXC__Work_Detail__c from SVMXC__Timesheet_Entry__c where SVMXC__Work_Detail__c IN :  workDetailIds limit 1];

trigger updateTimeEntriesHolidays on SVMXC__Service_Order_Line__c (after update) {

        //custom setting approach------------******* START
        Map<String, Holidays__mdt> holidays = Holidays__mdt.getAll();
        Map<Date, Holidays__mdt> holidaysMap = new Map<Date,Holidays__mdt>();

        
        Set<Id> workDetailIds = new Set<Id>();
        
        for(SVMXC__Service_Order_Line__c newLines : Trigger.New)
        {
            
            if (newLines.SVMX_PS_Customer_Start_Date__c != Trigger.oldMap.get(newLines.Id).SVMX_PS_Customer_Start_Date__c) {
                workDetailIds.add(newLines.Id);
            } 
        }
        
        
         for(Holidays__mdt ho: holidays.values())
         {
             holidaysMap.put(ho.Holiday_Date__c, ho);
         }
         

       SVMXC__Timesheet_Entry__c relatedTimeEntry = [Select ID, SVMXC__Work_Detail__c from SVMXC__Timesheet_Entry__c where SVMXC__Work_Detail__c IN :  workDetailIds limit 1];

        
                        
        List<SVMXC__Timesheet_Entry__c> TimeEntryToUpdate = new List<SVMXC__Timesheet_Entry__c>();
        
        
         for(SVMXC__Service_Order_Line__c wl: Trigger.New)
         {
              Date workDetailStartDate = wl.SVMX_PS_Customer_Start_Date__c;
             
              if(holidaysMap.containsKey(workDetailStartDate ))
              {
                  Date getDateHoliday =  holidaysMap.get(workDetailStartDate).Holiday_Date__c;
                  
                  if(workDetailStartDate == getDateHoliday)
                  {
                      SVMXC__Timesheet_Entry__c newTimeEntry = new SVMXC__Timesheet_Entry__c();
                      newTimeEntry.Id = relatedTimeEntry.Id;
                      newTimeEntry.isHoliday__c = TRUE;
                      TimeEntryToUpdate.add(newTimeEntry);
                  }
              }
              else
              {
                 SVMXC__Timesheet_Entry__c newTimeEntry = new SVMXC__Timesheet_Entry__c();
                      newTimeEntry.Id = relatedTimeEntry.Id;
                      newTimeEntry.isHoliday__c = False;
                      TimeEntryToUpdate.add(newTimeEntry);
              }
            
         }
         
         update TimeEntryToUpdate ;
         System.debug('TimeEntryToUpdate'+ TimeEntryToUpdate);
}