Expose isEnabled from underlying Sentry SDKs

[kodebach]

Problem Statement

We do not enable Sentry in all our app's build configurations. If it is disabled, we hide certain parts of the UI. For this we use Sentry.isEnabled(), which exists in both the JVM and Apple SDKs. However, it is not exposed in the multiplatform SDK, so we need to use a custom expect/actual function for that.

Solution Brainstorm

In io.sentry.kotlin.multiplatform.Sentry add isEnabled() that calls isEnabled() from the platform SDKs.

[buenaflor]

Thanks for the request 👍

Will add it