Resolves #211  ### Description Added validations for conversion metric configs. #### Rules pulled from #211 1. entity must exist in both the semantic models that the base_measure and conversion_measure are in 2. base_measure and conversion_measure must be valid and can only be SUM(1) or COUNT or DISTINCT_COUNT measures 3. In constant_properties, both property that is stated must be referencing either an existing dimension/entity in the respective base/conversion semantic model  ### Checklist - [x] I have read [the contributing guide](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md) and understand what's expected of me - [x] I have signed the [CLA](https://docs.getdbt.com/docs/contributor-license-agreements) - [x] This PR includes tests, or tests are not required/relevant for this PR - [x] I have run `changie new` to [create a changelog entry](https://github.com/dbt-labs/dbt-semantic-interfaces/blob/main/CONTRIBUTING.md#adding-a-changelog-entry)

Commits

Commits on Dec 6, 2023