Fix broken master; ensure all product service APIs have correct implementations (#20663)

* fix broken master; ensure all product service APIs are implemented by the structs passed to products

* use zero allocation interface checks

store/store.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/mattermost/mattermost-server/v6/model"
+	"github.com/mattermost/mattermost-server/v6/product"
 )
 
 type StoreResult struct {
@@ -1025,6 +1026,9 @@ type SidebarCategorySearchOpts struct {
 	ExcludeTeam bool
 }
 
+// Ensure store service adapter implements `product.StoreService`
+var _ product.StoreService = (*StoreServiceAdapter)(nil)
+
 // StoreServiceAdapter provides a simple Store wrapper for use with products.
 type StoreServiceAdapter struct {
 	store Store