redundant copying of config files in grafana role

[Jan Horstmann]

Some custom grafana configuration files are copied by both task `Copying over extra configuration file` as well as individual tasks later on.
While this does not pose any problem it is still redundant.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/kolla-ansible/+/921096

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/kolla-ansible/+/921096
Committed: https://opendev.org/openstack/kolla-ansible/commit/4178f02e2b549a6e5afd81cdb97086738be20b88
Submitter: "Zuul (22348)"
Branch: master

commit 4178f02e2b549a6e5afd81cdb97086738be20b88
Author: Jan Horstmann <email address hidden>
Date: Wed May 15 12:00:32 2024 +0200

    Fix redundant extra config files in grafana role

    Task `Check if extra configuration file exists` picks up all files in
    `{{ node_custom_config }}/grafana` including those that get handled
    specially later on.
    While `prometheus.yml` and `provisioning.yml` are best excluded from
    extra config , because their treatment requires more than just copying,
    `grafana_home_dashboard.json` may simply be treated as extra config,
    which saves the execution of two additional tasks.

    Closes-Bug: 2067999

    Change-Id: I7bce1fe3d0a96816f1782107b202d6dac7d1291d
    Signed-off-by: Jan Horstmann <email address hidden>