OSF: Used model.NewPointer everywhere (#27838)

```release-note
NONE
```

server/channels/app/import_test.go

@@ -295,10 +295,10 @@ func TestProcessAttachments(t *testing.T) {
 	genAttachments := func() *[]imports.AttachmentImportData {
 		return &[]imports.AttachmentImportData{
 			{
-				Path: model.NewString("file.jpg"),
+				Path: model.NewPointer("file.jpg"),
 			},
 			{
-				Path: model.NewString("somedir/file.jpg"),
+				Path: model.NewPointer("somedir/file.jpg"),
 			},
 		}
 	}
@@ -320,24 +320,24 @@ func TestProcessAttachments(t *testing.T) {
 	userLine := imports.LineImportData{
 		Type: "user",
 		User: &imports.UserImportData{
-			ProfileImage: model.NewString("profile.jpg"),
+			ProfileImage: model.NewPointer("profile.jpg"),
 		},
 	}
 
 	emojiLine := imports.LineImportData{
 		Type: "emoji",
 		Emoji: &imports.EmojiImportData{
-			Image: model.NewString("emoji.png"),
+			Image: model.NewPointer("emoji.png"),
 		},
 	}
 
 	t.Run("empty path", func(t *testing.T) {
 		expected := &[]imports.AttachmentImportData{
 			{
-				Path: model.NewString("file.jpg"),
+				Path: model.NewPointer("file.jpg"),
 			},
 			{
-				Path: model.NewString("somedir/file.jpg"),
+				Path: model.NewPointer("somedir/file.jpg"),
 			},
 		}
 
@@ -352,10 +352,10 @@ func TestProcessAttachments(t *testing.T) {
 	t.Run("valid path", func(t *testing.T) {
 		expected := &[]imports.AttachmentImportData{
 			{
-				Path: model.NewString("/tmp/file.jpg"),
+				Path: model.NewPointer("/tmp/file.jpg"),
 			},
 			{
-				Path: model.NewString("/tmp/somedir/file.jpg"),
+				Path: model.NewPointer("/tmp/somedir/file.jpg"),
 			},
 		}
 
@@ -499,7 +499,7 @@ func TestImportBulkImportWithAttachments(t *testing.T) {
 	}
 	require.NotNil(t, jsonFile)
 
-	th.App.UpdateConfig(func(cfg *model.Config) { cfg.TeamSettings.MaxUsersPerTeam = model.NewInt(1000) })
+	th.App.UpdateConfig(func(cfg *model.Config) { cfg.TeamSettings.MaxUsersPerTeam = model.NewPointer(1000) })
 
 	appErr, _ := th.App.BulkImportWithPath(th.Context, jsonFile, importZipReader, false, true, 1, model.ExportDataDir)
 	require.Nil(t, appErr)