fix: resolve issue with integration tests where lack of disk space caused k3s issues

[aaron-prindle]

fixes #2803

PR here adds a step to our integration test Github Action workflow to free up additional space to resolve issue where tests were failing to do not having enough disk space. See below:

Ongoing Kaniko CI/CD integration tests failures are related to disk pressure which is making it so the registry pod is not coming up properly (being evicted). Snippet of k3s status during failing run:

log link:
https://github.com/GoogleContainerTools/kaniko/actions/runs/6554012241/job/17800290036?pr=2804#step:6:127

log error snippet

...
       local-path-provisioner-957fdf8bc-h2b8x                1/1     Running     0          22m
            coredns-77ccd57875-9rd7w                              1/1     Running     0          22m
            helm-install-traefik-crd-fgmlk                        0/1     Completed   0          22m
            helm-install-local-registry-8zsth                     0/1     Completed   0          22m
            helm-install-traefik-wlmmz                            0/1     Completed   1          22m
            traefik-64f55bb67d-wv4b5                              1/1     Running     0          21m
            metrics-server-648b5df564-srtt4                       1/1     Running     0          22m
            local-registry-docker-registry-56d58d5d6-6dncc        0/1     Error       0          21m
            local-registry-docker-registry-56d58d5d6-sh4ls        0/1     Evicted     0          18s
            local-registry-docker-registry-56d58d5d6-tphm2        0/1     Pending     0          18s
            svclb-local-registry-docker-registry-c7ea5916-zggj6   0/1     Evicted     0          6s
            svclb-traefik-050d8b73-crcsf                          0/2     Evicted     0          0s

[JeromeJu]

LGTM