[Test] Fix test_patching_cluster failure by fixing the naming convention for patched AMIs

[gmarciani]

The prefix keeps the name from matching the pcluster AMI name filter, which is used by the tests to discover base AMI.

Without this change, test_patching_cluster will silently attempt to replace the head node ami with the patched ami when private OS are used, which causes a cluster update failure.

Description of changes

Fix test_patching_cluster failure by fixing the naming convention for patched AMIs

The naming is fixed by adding the prefix "patched-".

The prefix keeps the name from matching the pcluster AMI name filter, which is used by the tests to discover base AMI.

Without this change, test_patching_cluster will silently attempt to replace the head node ami with the patched ami when private OS are used, which causes a cluster update failure.

Tests

• Fixed the specific error on Rocky8 blocking cluster update

test-suites:
  patching:
    test_patching.py::test_patching_cluster:
      dimensions:
        - regions: [{{ g4dn_8xlarge_CAPACITY_RESERVATION_3_INSTANCES_2_HOURS_NOPG_rocky8 }}]
          instances: ["g4dn.8xlarge"]
          oss: ["rocky8"]
          schedulers: ["slurm"]
        - regions: [{{ g4dn_8xlarge_CAPACITY_RESERVATION_3_INSTANCES_2_HOURS_NOPG_ubuntu2204 }}]
          instances: ["g4dn.8xlarge"]
          oss: ["ubuntu2204"]
          schedulers: ["slurm"]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.