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.

Start by locating the self-signed-certificates-operator component and reviewing observability-stack PR #463 alongside self-signed-certificates-operator issue #591. Confirm that issue #591 is resolved, then inspect the component's temporary commit hash pin. Done means the pin is reverted and the component uses the appropriate revX tag.

Written by the indexing model from the issue text.