CI: add build step for the ObjCExample project

[andrii-bodnar]

Currently, we build only the Example project in the CI/CD build pipeline. We should build the ObjCExample project as well.

Related code: https://github.com/crowdin/mobile-sdk-ios/blob/master/.github/workflows/build.yml#L76C15-L76C26

[shreya-pramod]

Hi @andrii-bodnar

I would like to work on this issue. Could you please assign it to me?

[andrii-bodnar]

Hi @shreya-pramod, sure, thank you!

[andrii-bodnar]

@shreya-pramod any updates on this?