OSF: Used model.NewPointer everywhere (#27838)

```release-note
NONE
```

server/channels/app/plugin_test.go

@@ -479,7 +479,7 @@ func TestPluginSync(t *testing.T) {
 		{
 			"local",
 			func(cfg *model.Config) {
-				cfg.FileSettings.DriverName = model.NewString(model.ImageDriverLocal)
+				cfg.FileSettings.DriverName = model.NewPointer(model.ImageDriverLocal)
 			},
 		},
 		{
@@ -496,14 +496,14 @@ func TestPluginSync(t *testing.T) {
 				}
 
 				s3Endpoint := fmt.Sprintf("%s:%s", s3Host, s3Port)
-				cfg.FileSettings.DriverName = model.NewString(model.ImageDriverS3)
-				cfg.FileSettings.AmazonS3AccessKeyId = model.NewString(model.MinioAccessKey)
-				cfg.FileSettings.AmazonS3SecretAccessKey = model.NewString(model.MinioSecretKey)
-				cfg.FileSettings.AmazonS3Bucket = model.NewString(model.MinioBucket)
-				cfg.FileSettings.AmazonS3PathPrefix = model.NewString("")
-				cfg.FileSettings.AmazonS3Endpoint = model.NewString(s3Endpoint)
-				cfg.FileSettings.AmazonS3Region = model.NewString("")
-				cfg.FileSettings.AmazonS3SSL = model.NewBool(false)
+				cfg.FileSettings.DriverName = model.NewPointer(model.ImageDriverS3)
+				cfg.FileSettings.AmazonS3AccessKeyId = model.NewPointer(model.MinioAccessKey)
+				cfg.FileSettings.AmazonS3SecretAccessKey = model.NewPointer(model.MinioSecretKey)
+				cfg.FileSettings.AmazonS3Bucket = model.NewPointer(model.MinioBucket)
+				cfg.FileSettings.AmazonS3PathPrefix = model.NewPointer("")
+				cfg.FileSettings.AmazonS3Endpoint = model.NewPointer(s3Endpoint)
+				cfg.FileSettings.AmazonS3Region = model.NewPointer("")
+				cfg.FileSettings.AmazonS3SSL = model.NewPointer(false)
 			},
 		},
 	}