Rename `SentryMechanismMeta` to something else different than `Meta`

### Description

Running into this issue right now: https://github.com/getsentry/sentry-kotlin-multiplatform/blob/d5ecbdf84b0a7881ed9664715436f34c8d8072c8/sentry-kotlin-multiplatform/build.gradle.kts#L178-L185