Javascript-SDK - 1.3.5

* Bump optimizely-server-sdk to version 1.2.3, which includes:
- Switched to json-schema library which has a smaller footprint.
- Refactored order of bucketing logic.
- Refactor lodash dependencies.
- Fixed error on validation for objects with undefined values for attributes.

https://github.com/optimizely/javascript-sdk/releases/tag/1.3.5