Plugins: Migrate PluginStore mock to pre-existing fakes package (#71664)

* migrate to existing fakes package

* fix imports

pkg/services/provisioning/plugins/config_reader_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/plugins/manager/fakes"
 )
 
 const (
@@ -33,7 +34,7 @@ func TestConfigReader(t *testing.T) {
 	})
 
 	t.Run("Unknown app plugin should return error", func(t *testing.T) {
-		cfgProvider := newConfigReader(log.New("test logger"), plugins.FakePluginStore{})
+		cfgProvider := newConfigReader(log.New("test logger"), &fakes.FakePluginStore{})
 		_, err := cfgProvider.readConfig(context.Background(), unknownApp)
 		require.Error(t, err)
 		require.Equal(t, "plugin not installed: \"nonexisting\"", err.Error())
@@ -47,7 +48,7 @@ func TestConfigReader(t *testing.T) {
 	})
 
 	t.Run("Can read correct properties", func(t *testing.T) {
-		pm := plugins.FakePluginStore{
+		pm := &fakes.FakePluginStore{
 			PluginList: []plugins.PluginDTO{
 				{JSONData: plugins.JSONData{ID: "test-plugin"}},
 				{JSONData: plugins.JSONData{ID: "test-plugin-2"}},