[MM-17422] Added code to update, delete last bot_icon time in model.bot. (#12229)

Display LHS bot Icon in web app. As part of mentioned task, Added LastIconUpdate variable in model.bot to store last update time of icon. Also added code to update/delete value of the mentioned variable when setting/deleting bot icon.

app/bot.go

@@ -328,7 +328,8 @@ func (a *App) SetBotIconImageFromMultiPartFile(botUserId string, imageData *mult
 
 // SetBotIconImage sets LHS icon for a bot.
 func (a *App) SetBotIconImage(botUserId string, file io.ReadSeeker) *model.AppError {
-	if _, err := a.GetBot(botUserId, true); err != nil {
+	bot, err := a.GetBot(botUserId, true)
+	if err != nil {
 		return err
 	}
 
@@ -338,12 +339,13 @@ func (a *App) SetBotIconImage(botUserId string, file io.ReadSeeker) *model.AppEr
 
 	// Set icon
 	file.Seek(0, 0)
-	if _, err := a.WriteFile(file, getBotIconPath(botUserId)); err != nil {
+	if _, err = a.WriteFile(file, getBotIconPath(botUserId)); err != nil {
 		return model.NewAppError("SetBotIconImage", "api.bot.set_bot_icon_image.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
-	if err := a.Srv.Store.User().UpdateLastPictureUpdate(botUserId); err != nil {
-		mlog.Error(err.Error())
+	bot.LastIconUpdate = model.GetMillis()
+	if _, err = a.Srv.Store.Bot().Update(bot); err != nil {
+		return err
 	}
 	a.invalidateUserCacheAndPublish(botUserId)
 
@@ -352,18 +354,25 @@ func (a *App) SetBotIconImage(botUserId string, file io.ReadSeeker) *model.AppEr
 
 // DeleteBotIconImage deletes LHS icon for a bot.
 func (a *App) DeleteBotIconImage(botUserId string) *model.AppError {
-	if _, err := a.GetBot(botUserId, true); err != nil {
+	bot, err := a.GetBot(botUserId, true)
+	if err != nil {
 		return err
 	}
 
 	// Delete icon
-	if err := a.RemoveFile(getBotIconPath(botUserId)); err != nil {
+	if err = a.RemoveFile(getBotIconPath(botUserId)); err != nil {
 		return model.NewAppError("DeleteBotIconImage", "api.bot.delete_bot_icon_image.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
-	if err := a.Srv.Store.User().UpdateLastPictureUpdate(botUserId); err != nil {
+	if err = a.Srv.Store.User().UpdateLastPictureUpdate(botUserId); err != nil {
 		mlog.Error(err.Error())
 	}
+
+	bot.LastIconUpdate = int64(0)
+	if _, err = a.Srv.Store.Bot().Update(bot); err != nil {
+		return err
+	}
+
 	a.invalidateUserCacheAndPublish(botUserId)
 
 	return nil