Remove jdbc: modifier from SWELL_DB_URL

[gwright99]

As per https://github.com/seqeralabs/groundswell/pull/98#pullrequestreview-1952618849, the jdbc: modifier is not required when populating the SWELL_DB_URL configuration value.

While this does not appear to break the Docker-Compose implementation (due to a stripping function with the Groundswell container itself), the value should be removed to ensure more consistent harmonization with the Seqera Platform K8s deployment and docs.seqera.io guidance.