Tracking: Disable scale-in, scale-out tests in gate until they have stabalised

The scale-in, scale-out tests break the gate (randomly) as there seem to be races in the charm when adding and removing units that result in unhealthy clusters.

e.g.

Model Controller Cloud/Region Version SLA Timestamp
zaza-16f2385aed4c auto-osci-sv10 serverstack/serverstack 2.8.7 unsupported 21:02:02Z

App Version Status Scale Charm Store Rev OS Notes
keystone 17.0.0 active 1 keystone jujucharms 530 ubuntu
keystone-mysql-router 8.0.23 active 1 mysql-router jujucharms 39 ubuntu
mysql-innodb-cluster 8.0.23 blocked 3 mysql-innodb-cluster local 0 ubuntu
vault 1.5.4 active 1 vault jujucharms 130 ubuntu
vault-mysql-router 8.0.23 active 1 mysql-router jujucharms 39 ubuntu

Unit Workload Agent Machine Public address Ports Message
keystone/0* active idle 0 172.17.110.3 5000/tcp Unit is ready
  keystone-mysql-router/0* active idle 172.17.110.3 Unit is ready
mysql-innodb-cluster/1* active idle 2 172.17.110.24 Unit is ready: Mode: R/W
mysql-innodb-cluster/2 active idle 3 172.17.110.6 Unit is ready: Mode: R/O
mysql-innodb-cluster/4 blocked idle 6 172.17.110.5 MySQL InnoDB Cluster not healthy: None
vault/0* active idle 4 172.17.110.17 8200/tcp Unit is ready (active: true, mlock: enabled)
  vault-mysql-router/0* active idle 172.17.110.17 Unit is ready

Machine State DNS Inst id Series AZ Message
0 started 172.17.110.3 50a056f5-914e-476e-9b38-4c6c378c2de9 focal nova ACTIVE
2 started 172.17.110.24 ee1ba859-08e5-41a4-b666-c83c5d30317e focal nova ACTIVE
3 started 172.17.110.6 d1e6d7f3-dc6b-4fa0-840d-fd3fd86b752c focal nova ACTIVE
4 started 172.17.110.17 c02bd4b8-fefd-426a-9ee2-93e564fe8aa4 focal nova ACTIVE
6 started 172.17.110.5 d3e7bebf-2da5-4a4d-8539-6a896fe33fbb focal nova ACTIVE

This bug is to track and ensure that the tests get added back into get when the problem has been resolved.

The tests will be moved to development bundles.