mgr/dashboard: run-cephadm-e2e-tests.sh improvements

mgr/dashboard: run-cephadm-e2e-tests.sh improvements

- Jenkins env.: make sure the cluster is always started.
- PR template: add trigger phrase to the jenkins commands list.
- Cypress: add --no-install flag; clean previous reports.

Fixes: https://tracker.ceph.com/issues/52082
Signed-off-by: Alfonso Martínez <almartin@redhat.com>
(cherry picked from commit cadf8c75ac0266e42c1ea0b4d6733590ea3dac21)

 Conflicts:
	.github/pull_request_template.md
      - Update jenkins trigger phrases: cephadm e2e; api tests.