[HEALTCHECK] remove mariadbgalera connectivity tests from core
it was mentioned in the patch review but not takent into account
using core tag leads to errors in core [1]
because the xtesting HC docker does not include kubecl, which is needed by the new tests
Issue-ID: SO-3829
[1]: https://logs.onap.org/onap-integration/daily/onap_daily_pod4_master/2022-01/21_01-42/xtesting-healthcheck/core/core/report.html#totals?all
Signed-off-by: morganrol <morgan.richomme@orange.com>
Change-Id: I1d8e93dec80ecdfa0cdcabaefb961f77f0654849