[Chore/Refactor] Add missing 'type' attribute on 'button' components (#26249)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: asukaminato0721 <30024051+asukaminato0721@users.noreply.github.com>

web/app/components/base/date-and-time-picker/calendar/item.tsx

@@ -13,7 +13,7 @@ const Item: FC<CalendarItemProps> = ({
   const isToday = date.isSame(dayjs(), 'date')
 
   return (
-    <button
+    <button type="button"
       onClick={() => onClick(date)}
       className={cn(
         'system-sm-medium relative flex items-center justify-center rounded-lg px-1 py-2',

web/app/components/base/date-and-time-picker/date-picker/header.tsx

@@ -14,7 +14,7 @@ const Header: FC<DatePickerHeaderProps> = ({
   return (
     <div className='mx-2 mt-2 flex items-center'>
       <div className='flex-1'>
-        <button
+        <button type="button"
           onClick={handleOpenYearMonthPicker}
           className='system-md-semibold flex items-center gap-x-0.5 rounded-lg px-2 py-1.5 text-text-primary hover:bg-state-base-hover'
         >
@@ -22,13 +22,13 @@ const Header: FC<DatePickerHeaderProps> = ({
           <RiArrowDownSLine className='h-4 w-4 text-text-tertiary' />
         </button>
       </div>
-      <button
+      <button type="button"
         onClick={onClickPrevMonth}
         className='rounded-lg p-1.5 hover:bg-state-base-hover'
       >
         <RiArrowUpSLine className='h-[18px] w-[18px] text-text-secondary' />
       </button>
-      <button
+      <button type="button"
         onClick={onClickNextMonth}
         className='rounded-lg p-1.5 hover:bg-state-base-hover'
       >

web/app/components/base/date-and-time-picker/year-and-month-picker/header.tsx

@@ -13,7 +13,7 @@ const Header: FC<YearAndMonthPickerHeaderProps> = ({
   return (
     <div className='flex border-b-[0.5px] border-divider-regular p-2 pb-1'>
       {/* Year and Month */}
-      <button
+      <button type="button"
         onClick={onClick}
         className='system-md-semibold flex items-center gap-x-0.5 rounded-lg px-2 py-1.5 text-text-primary hover:bg-state-base-hover'
       >