[MM-57356] Make use of go1.21 features (#26620)

server/channels/store/searchtest/testlib.go

@@ -4,10 +4,9 @@
 package searchtest
 
 import (
+	"slices"
 	"testing"
 
-	pUtils "github.com/mattermost/mattermost/server/public/utils"
-
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 )
 
@@ -36,12 +35,12 @@ type searchTest struct {
 func filterTestsByTag(tests []searchTest, tags ...string) []searchTest {
 	filteredTests := []searchTest{}
 	for _, test := range tests {
-		if pUtils.Contains(test.Tags, EngineAll) {
+		if slices.Contains(test.Tags, EngineAll) {
 			filteredTests = append(filteredTests, test)
 			continue
 		}
 		for _, tag := range tags {
-			if pUtils.Contains(test.Tags, tag) {
+			if slices.Contains(test.Tags, tag) {
 				filteredTests = append(filteredTests, test)
 				break
 			}