[AI-FSSDK] [FSSDK-12337] Add Feature Rollout support (#524)

* [FSSDK-12337] Bump core-api version for Feature Rollout support

Update java_core_ver to 4.4.0-SNAPSHOT to pick up Feature Rollout
support from the Java SDK core-api. The Android SDK is a wrapper
around core-api, so the Experiment type field, config parsing, and
rollout variation injection are all handled by the Java SDK.

This version will be updated to the final release version once the
Java SDK publishes core-api with feature rollout support.

* fix java core version

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Co-authored-by: Jae Kim <jae.kim@optimizely.com>

Author: FarhanAnjum-opti