Remove unnecessary conversion in mutable state

[wxing1292]

Is your feature request related to a problem? Please describe.

temporal/service/history/mutableStateBuilder.go

Lines 3900 to 3913 in 4173272

	UpsertActivityInfos: convertUpdateActivityInfos(e.updateActivityInfos),
	DeleteActivityInfos: convertDeleteActivityInfos(e.deleteActivityInfos),
	UpsertTimerInfos: convertUpdateTimerInfos(e.updateTimerInfos),
	DeleteTimerInfos: convertDeleteTimerInfos(e.deleteTimerInfos),
	UpsertChildExecutionInfos: convertUpdateChildExecutionInfos(e.updateChildExecutionInfos),
	DeleteChildExecutionInfo: e.deleteChildExecutionInfo,
	UpsertRequestCancelInfos: convertUpdateRequestCancelInfos(e.updateRequestCancelInfos),
	DeleteRequestCancelInfo: e.deleteRequestCancelInfo,
	UpsertSignalInfos: convertUpdateSignalInfos(e.updateSignalInfos),
	DeleteSignalInfo: e.deleteSignalInfo,
	UpsertSignalRequestedIDs: convertStringSetToSlice(e.updateSignalRequestedIDs),
	DeleteSignalRequestedID: e.deleteSignalRequestedID,
	NewBufferedEvents: e.updateBufferedEvents,
	ClearBufferedEvents: e.clearBufferedEvents,

Above conversions are unnecessary