Add io.Closer guidelines (#29387)

Co-authored-by: Yarden Shoham <git@yardenshoham.com>

modules/indexer/internal/bleve/indexer.go

@@ -92,7 +92,7 @@ func (i *Indexer) Ping(_ context.Context) error {
 }
 
 func (i *Indexer) Close() {
-	if i == nil {
+	if i == nil || i.Indexer == nil {
 		return
 	}
 

modules/indexer/internal/meilisearch/indexer.go

@@ -87,8 +87,5 @@ func (i *Indexer) Close() {
 	if i == nil {
 		return
 	}
-	if i.Client == nil {
-		return
-	}
 	i.Client = nil
 }