MM-56879: Migrate caches from store layer to cache layer (#26255)

There were 3 remaining caches which were there in the store layer.
We migrate them to make the store layer fully free
from any caches.

https://mattermost.atlassian.net/browse/MM-56879

```release-note
NONE
```

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/import_functions.go

@@ -1417,7 +1417,7 @@ func (a *App) getChannelsForPosts(teams map[string]*model.Team, data []*imports.
 		channelName := strings.ToLower(*postData.Channel)
 		if channel, ok := teamChannels[teamName][channelName]; !ok || channel == nil {
 			var err error
-			channel, err = a.Srv().Store().Channel().GetByName(teams[teamName].Id, *postData.Channel, true)
+			channel, err = a.Srv().Store().Channel().GetByNameIncludeDeleted(teams[teamName].Id, *postData.Channel, true)
 			if err != nil {
 				return nil, model.NewAppError("BulkImport", "app.import.import_post.channel_not_found.error", map[string]any{"ChannelName": *postData.Channel}, "", http.StatusBadRequest).Wrap(err)
 			}