don't allow deletedAt to be set when creating user (#23914)

server/public/model/user.go

@@ -669,6 +669,7 @@ func (u *User) SanitizeInput(isAdmin bool) {
 		u.AuthService = ""
 		u.EmailVerified = false
 	}
+	u.DeleteAt = 0
 	u.LastPasswordUpdate = 0
 	u.LastPictureUpdate = 0
 	u.FailedAttempts = 0