Add post-install scripts to all tests to capture failure details in GitHub workflow summary (#88)

.github/tests/spire-oidc-insecure/pre-install.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
-SCRIPT=$(readlink -f "$0")
-SCRIPTPATH=$(dirname "${SCRIPT}")
+SCRIPT="$(readlink -f "$0")"
+SCRIPTPATH="$(dirname "${SCRIPT}")"
 scenario="${scenario:-$(basename "${SCRIPTPATH}")}"
 
 helm install ingress-nginx ingress-nginx --version "${VERSION_INGRESS_NGINX}" --repo "${HELM_REPO_INGRESS_NGINX}" -n "$scenario" --set controller.extraArgs.enable-ssl-passthrough=