MM-14145: The config store Set will now Save automatically (#10377)

* MM-14145: The config store Set will now Save automatically

When UpdateConfig (and configStore.Set) is called in admin.go and
config.go, commonStore.Set now takes a store-specific persist function.
It uses that persist function to save the configuration automatically.

Removed: Now callers do not have to call configStore.Save or
app.PersistConfig, and those functions have been removed.

Possible downside: this means a "failed to persist config" error can now
be thrown during a app.UpdateConfig or commonStore.Set call. But
considering application code never really sets a config without saving
it (except in the test cases, which were testing that -- see below), it
seems fine to group these responsibilities.

Also removed: tests for 'set without save'. Since that can not happen
anymore, the tests are not needed.

* Removed Save completely, cleaned up formatting, joined save test with
set tests.

* fixed shadowed variable error

config/database_test.go

@@ -268,6 +268,29 @@ func TestDatabaseStoreSet(t *testing.T) {
 		assert.Equal(t, "http://new", *ds.Get().ServiceSettings.SiteURL)
 	})
 
+	t.Run("set with automatic save", func(t *testing.T) {
+		_, tearDown := setupConfigDatabase(t, minimalConfig)
+		defer tearDown()
+
+		ds, err := config.NewDatabaseStore(fmt.Sprintf("%s://%s", *sqlSettings.DriverName, *sqlSettings.DataSource))
+		require.NoError(t, err)
+		defer ds.Close()
+
+		newCfg := &model.Config{
+			ServiceSettings: model.ServiceSettings{
+				SiteURL: sToP("http://new"),
+			},
+		}
+
+		_, err = ds.Set(newCfg)
+		require.NoError(t, err)
+
+		err = ds.Load()
+		require.NoError(t, err)
+
+		assert.Equal(t, "http://new", *ds.Get().ServiceSettings.SiteURL)
+	})
+
 	t.Run("persist failed", func(t *testing.T) {
 		t.Skip("skipping persistence test inside Set")
 		_, tearDown := setupConfigDatabase(t, emptyConfig)
@@ -421,45 +444,6 @@ func TestDatabaseStoreLoad(t *testing.T) {
 	})
 }
 
-func TestDatabaseStoreSave(t *testing.T) {
-	_, tearDown := setupConfigDatabase(t, minimalConfig)
-	defer tearDown()
-
-	sqlSettings := mainHelper.GetSqlSettings()
-	ds, err := config.NewDatabaseStore(fmt.Sprintf("%s://%s", *sqlSettings.DriverName, *sqlSettings.DataSource))
-	require.NoError(t, err)
-	defer ds.Close()
-
-	newCfg := &model.Config{
-		ServiceSettings: model.ServiceSettings{
-			SiteURL: sToP("http://new"),
-		},
-	}
-
-	t.Run("set without save", func(t *testing.T) {
-		_, err = ds.Set(newCfg)
-		require.NoError(t, err)
-
-		err = ds.Load()
-		require.NoError(t, err)
-
-		assert.Equal(t, "http://minimal", *ds.Get().ServiceSettings.SiteURL)
-	})
-
-	t.Run("set with save", func(t *testing.T) {
-		_, err = ds.Set(newCfg)
-		require.NoError(t, err)
-
-		err = ds.Save()
-		require.NoError(t, err)
-
-		err = ds.Load()
-		require.NoError(t, err)
-
-		assert.Equal(t, "http://new", *ds.Get().ServiceSettings.SiteURL)
-	})
-}
-
 func TestDatabaseStoreString(t *testing.T) {
 	_, tearDown := setupConfigDatabase(t, emptyConfig)
 	defer tearDown()