(fix) Adding extra slice variables in helm chart

charts/oai-5g-core/oai-5g-basic/values.yaml

charts/oai-5g-core/oai-5g-mini/values.yaml

charts/oai-5g-core/oai-5g-slicing/values.yaml

charts/oai-5g-ran/oai-gnb-du/values.yaml

docker-compose/docker-compose-basic-nrf-http2.yaml

docs/BUILD_IMAGES.md

docs/DEPLOY_SA5G_BASIC_DEPLOYMENT.md

docs/DEPLOY_SA5G_BASIC_STATIC_UE_IP.md

docs/DEPLOY_SA5G_WITH_My5g-RANTester.md

docs/RETRIEVE_OFFICIAL_IMAGES.md