Implement integration of telemetry client into internal theme packages

[larsrickert]

Why?

‼️ Only for non-public / Schwarz internal theme packages

In #3829, we implemented the telemetry client. We now want to integrate it into the Schwarz internal npm packages so the telemetry records are saved when installing on of those themes.

Acceptance criteria

• the @onyx-internal/telemetry-client package is defined as a dependency of every Schwarz internal theme which thenruns a postinstall script that executes the telemetry client
• it is ensured that the client runs correctly with pnpm which blocks postinstall scripts unless explicitly allowed by the project

DEV handover checklist

DEV handover done with: @ADD_DEV_NAME_HERE

Testing

• covered by functional tests (Playwright or unit test)

Documentation

• updated version is released

Other

• follow-up tickets were created if necessary (add links below)