Refactor: func StringInSlice to slices.Contains (#24262)

* Refactor: Use generic to change func StringInSlice to Contains

* Refactor: Use generic to change func stringNotInSlice to Contains

Make utils.go (dir server/public/utils) and func Contains

* Refactor: Move func Contains from channels/utils to public/utils

Move func Contains from channels/utils to public/utils

Fix import declarations line

* Docs: Add a description of the Contains function

* Test: add TestContains

Add a test code for a Contain function

server/channels/api4/user.go

@@ -14,6 +14,8 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	pUtils "github.com/mattermost/mattermost/server/public/utils"
+
 	"github.com/mattermost/mattermost/server/v8/channels/app"
 	"github.com/mattermost/mattermost/server/v8/channels/audit"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
@@ -722,7 +724,7 @@ func getUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 			c.SetInvalidParam("role")
 			return
 		}
-		roleValid := utils.StringInSlice(role, roleNamesAll)
+		roleValid := pUtils.Contains(roleNamesAll, role)
 		if !roleValid {
 			c.SetInvalidParam("role")
 			return

server/channels/api4/user_local.go

@@ -11,6 +11,8 @@ import (
 
 	"github.com/mattermost/mattermost/server/public/model"
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
+	pUtils "github.com/mattermost/mattermost/server/public/utils"
+
 	"github.com/mattermost/mattermost/server/v8/channels/audit"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 	"github.com/mattermost/mattermost/server/v8/channels/utils"
@@ -85,7 +87,7 @@ func localGetUsers(c *Context, w http.ResponseWriter, r *http.Request) {
 			c.SetInvalidParam("role")
 			return
 		}
-		roleValid := utils.StringInSlice(role, roleNamesAll)
+		roleValid := pUtils.Contains(roleNamesAll, role)
 		if !roleValid {
 			c.SetInvalidParam("role")
 			return