MTFF: Allow viewers access in cloud (#114607)

* Reapply "K8s: read resource configs from API Enablement for API Builders" (#114475)

This reverts commit 4130bd9cd3.

* revert part that broke things

* FF service changes are gonna come later

* MTFF: allow viewers access to MTFF by enforcing runtime_config for custom routes

* unused var

* removed now

* pass the test, include defaults

* revert sample.ini change

pkg/tests/testinfra/testinfra.go

@@ -316,6 +316,21 @@ func CreateGrafDir(t *testing.T, opts GrafanaOpts) (string, string) {
 	_, err = serverSect.NewKey("static_root_path", publicDir)
 	require.NoError(t, err)
 
+	openFeatureSect, err := cfg.NewSection("feature_toggles.openfeature")
+	require.NoError(t, err)
+	_, err = openFeatureSect.NewKey("enable_api", strconv.FormatBool(opts.OpenFeatureAPIEnabled))
+	require.NoError(t, err)
+	if !opts.OpenFeatureAPIEnabled {
+		_, err = openFeatureSect.NewKey("provider", "static") // in practice, APIEnabled being false goes with goff type, but trying to make tests work
+		require.NoError(t, err)
+		_, err = openFeatureSect.NewKey("targetingKey", "grafana")
+		require.NoError(t, err)
+
+		// so staticFlags can be provided to static provider
+		_, err := cfg.NewSection("feature_toggles")
+		require.NoError(t, err)
+	}
+
 	anonSect, err := cfg.NewSection("auth.anonymous")
 	require.NoError(t, err)
 	_, err = anonSect.NewKey("enabled", "true")
@@ -654,6 +669,7 @@ type GrafanaOpts struct {
 	DisableDBCleanup                      bool
 	DisableDataMigrations                 bool
 	SecretsManagerEnableDBMigrations      bool
+	OpenFeatureAPIEnabled                 bool
 
 	// Allow creating grafana dir beforehand
 	Dir     string