[Provider]: Add unleash web provider for JS

### SDK

JavaScript/TypeScript

### Vendor/Tool

Unleash

### Maintainer

Community

### Artifacts

Pending release:
https://github.com/open-feature/js-sdk-contrib/pull/1105

### Repository
once above PR is merged -  
https://github.com/open-feature/js-sdk-contrib/tree/main/libs/providers/unleash-web

### Anything else?

_No response_