fix(demo): add missing TaskDB among demo sqlDbs

[francescobrivio]

PR Description

This PR includes in the demo chart the TaskDB sqlDB which was missing from the list.
This is needed to fix the failing integration test in DIRACGrid/diracx#1034, specifically this test which reports:

    File "/app/.pixi/envs/container-services/lib/python3.11/site-packages/diracx/db/sql/utils/base.py", line 140, in available_urls
      raise Exception(
  Exception: TaskDB found but no URL connection set: please set the DIRACX_DB_URL_TASKDB env variable to enable it.

Which incidentally validates the diracx PR itself 😄