fix: improve operator name capture in uninstall script

[vprashar2929]

This PR updates the uninstall script for capturing the operator name. The previous method was not optimal and was prone to error in cases where the user uninstalled any previous operator using UI. oc get operators will still show the operator being present.

For eg:

oc get subs -A ; oc get operators                                                           
NAMESPACE             NAME                             PACKAGE                          SOURCE             CHANNEL
openshift-operators   cluster-observability-operator   cluster-observability-operator   redhat-operators   development
NAME                                                 AGE
cluster-observability-operator.openshift-operators   59m
kepler-operator.openshift-operators                  27m
power-monitoring-operator.openshift-operators        9h

[vimalk78]

/lgtm