SbcHeader + Auth Web: remove What's New feature flag

We would like the What's New feature (in the SbcHeader) to be displayed in all UIs.

Currently, this feature requires a feature flag (`whats-new`) in the "sbc-auth" LaunchDarkly project. Most of the subject UIs use a different LaunchDarkly project. Therefore, and since What's New is deployed to and enabled in Prod, it is proposed to simply remove the feature flag check in SbcHeader.

This ticket is to include:
- [ ] remove `whats-new` FF check from SbcHeader component
- [ ] publish new sbc-common-components
- [ ] import new sbc-common-components into Auth Web UI
- [ ] when Auth Web UI is deployed to Prod, delete this FF from LaunchDarkly

Other tickets will be created to import the new sbc-common-components into other UIs.

cc: @jyoti3286 @SateeshFW @lmcclung

Start by locating the SbcHeader component and the sbc-common-components package, then trace how Auth Web UI imports that package. Confirm the What's New flag check is removed, publish the updated package, and update Auth Web UI to use it. Done means the Auth Web UI is deployed with What's New enabled without the flag and the LaunchDarkly flag can be deleted.

Written by the indexing model from the issue text.