GraphQL: Create dedicated top-level filter for sidebar categories (#20353)

We add the excludeTeam switch to allow user to get
all sidebar categories from other teams excluding a given team.

```release-note
NONE
```

app/plugin_api.go

@@ -493,7 +493,7 @@ func (api *PluginAPI) CreateChannelSidebarCategory(userID, teamID string, newCat
 }
 
 func (api *PluginAPI) GetChannelSidebarCategories(userID, teamID string) (*model.OrderedSidebarCategories, *model.AppError) {
-	return api.app.GetSidebarCategories(userID, teamID)
+	return api.app.GetSidebarCategoriesForTeamForUser(userID, teamID)
 }
 
 func (api *PluginAPI) UpdateChannelSidebarCategories(userID, teamID string, categories []*model.SidebarCategoryWithChannels) ([]*model.SidebarCategoryWithChannels, *model.AppError) {