Fix Allure Report (#8)

Rename machines spread variants to match Kubernetes spread variants

Machines results missing from
https://canonical.github.io/mysql-router-operators/7/

This may not fully fix the Allure Report—it looks like if the relative
path to the test file and the test name is the same, the test case ID
may be identical, so for those tests vm/k8s may override each other.
However, this should at least fix zero results for machines showing up
in the Allure Report

Author: carlcsaposs-canonical

machines/spread.yaml

@@ -96,7 +96,7 @@ backends:
       - ubuntu-24.04-arm:
           username: runner
           variants:
-            - -juju29_ubuntu22
+            - -juju29
 
 suites:
   tests/spread/:
@@ -107,9 +107,9 @@ path: /root/spread_project
 kill-timeout: 3h
 environment:
   PATH: $PATH:$(pipx environment --value PIPX_BIN_DIR)
-  CONCIERGE_JUJU_CHANNEL/juju36_ubuntu22: 3.6/stable
-  CONCIERGE_JUJU_CHANNEL/juju29_ubuntu22: 2.9/stable
-  CHARM_UBUNTU_BASE/juju36_ubuntu22,juju29_ubuntu22: 22.04
+  CONCIERGE_JUJU_CHANNEL/juju36: 3.6/stable
+  CONCIERGE_JUJU_CHANNEL/juju29: 2.9/stable
+  CHARM_UBUNTU_BASE/juju36,juju29: 22.04
 prepare: |
   snap refresh --hold
   chown -R root:root "$SPREAD_PATH"