ci/qcom-devicepkg-bootimg: configure job to only run manually, ignore failure

The hw CI isn't stable yet, if a platform is entirely offline (e.g.
because we only have 1 device in CI and it's down for maint.) then the
test job is "pending" for a verrrry long time (16hrs+). mrtest (for
example) is then unable to be used on the MR because the pipeline is
not "success."

Signed-off-by: Clayton Craft <craftyguy@postmarketos.org>
Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/7943>

device/.gitlab-ci/packages/single-runner-defined-in-ci-common-qcom-devicepkg-bootimg.yml.j2

@@ -14,6 +14,11 @@ test-{{ device.name }}:
     - .device-boot-flow-separate-artifacts
     - .test-{{ device.name }}
 
+  # NOTE: set the job to manually started and allow failure until HW CI is
+  # stable
+  allow_failure: true
+  when: manual
+
   variables:
     # Let CI-tron construct the bootimg accepted by U-boot in a standard
     # Qualcomm way