Revert "Secrets: Remove unused register_api_server setting" (#116004)

Revert "Secrets: Remove unused register_api_server setting (#113849)"

This reverts commit 4ee2112ea4.

pkg/setting/setting_secrets_manager_test.go

@@ -171,6 +171,28 @@ domain = example.com
 		assert.Empty(t, cfg.SecretsManagement.ConfiguredKMSProviders)
 	})
 
+	t.Run("should handle configuration with register_api_server disabled", func(t *testing.T) {
+		iniContent := `
+[secrets_manager]
+register_api_server = false
+`
+		cfg, err := NewCfgFromBytes([]byte(iniContent))
+		require.NoError(t, err)
+
+		assert.False(t, cfg.SecretsManagement.RegisterAPIServer)
+	})
+
+	t.Run("should handle configuration without register_api_server set", func(t *testing.T) {
+		iniContent := `
+[secrets_manager]
+encryption_provider = aws_kms
+`
+		cfg, err := NewCfgFromBytes([]byte(iniContent))
+		require.NoError(t, err)
+
+		assert.True(t, cfg.SecretsManagement.RegisterAPIServer)
+	})
+
 	t.Run("should handle configuration with run_secrets_db_migrations disabled", func(t *testing.T) {
 		iniContent := `
 [secrets_manager]