bug(besu): mysql commands fail during tessera deployment

[alvaropicazo]

Describe the bug
When running the besu-node helm chart to deploy a Besu node & Tessera node, a demouser and root user are created on mysql db running within the Tessera pod.

PASSWORD('$pass') function is deprecated for mysql version 8+

To Reproduce
Steps to reproduce the behavior:

1. Deploy the besu node chart with tessera flag enabled
2. Run kubectl logs 'tessera_pod' -n 'namespace_id' and check the output. Errors while creating the users will be displayed