Remove hard-coded kusto ingestion variable in dotnet-docker pipelines (#7075)

Author: lbussell

eng/docker-tools/templates/variables/common.yml

@@ -6,8 +6,6 @@ variables:
   value: true
 - name: publishImageInfo
   value: true
-- name: ingestKustoImageInfo
-  value: true
   # CG is disabled by default because projects are built within Dockerfiles and CG step do not scan artifacts
   # that are built within Dockerfiles. A separate CG pipeline exists for this reason.
 - name: skipComponentGovernanceDetection