fix(chart): updated chart name to `istio-gateway` from `gateway`
General MR
Summary
This MR updates the helm chart name for the istio-gateway
package to istio-gateway
Relevant logs/screenshots
N/A
Linked Issue
Upgrade Notices
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UNCLASSIFIED - NO CUI
Currently supported Big Bang Version is 3.7.1
UNCLASSIFIED - NO CUI