Revert "[MM-8497] Ability to set Do Not Disturb for a specified period of time (#16067)" (#17657)

This reverts commit 77d42568f9.

model/status.go

@@ -25,8 +25,6 @@ type Status struct {
 	Manual         bool   `json:"manual"`
 	LastActivityAt int64  `json:"last_activity_at"`
 	ActiveChannel  string `json:"active_channel,omitempty" db:"-"`
-	DNDEndTime     int64  `json:"dnd_end_time"`
-	PrevStatus     string `json:"-"`
 }
 
 func (o *Status) ToJson() string {