Support for Juju v4 in our products

This PR is a workaround for getting proper TF Juju provider v2 support from the self-signed-certificates-operator TF module:
- https://github.com/canonical/observability-stack/pull/463

However, once this issue is resoled:
- https://github.com/canonical/self-signed-certificates-operator/issues/591

We should revert the tempory commit hash pin in the SSC component and switch to a `revX` tag.