MM-21898 - Part 1: Generate and use an interface instead of *A… (#13840)

* Generate and use an interface instead of *App

app/plugin_test.go

@@ -73,7 +73,7 @@ func TestPluginKeyValueStore(t *testing.T) {
 		ExpireAt: 0,
 	}
 
-	_, err = th.App.Srv.Store.Plugin().SaveOrUpdate(kv)
+	_, err = th.App.Srv().Store.Plugin().SaveOrUpdate(kv)
 	assert.Nil(t, err)
 
 	// Test fetch by keyname (this key does not exist but hashed key will be used for lookup)