Backport of NET-11798: Set APIGateway TLSConfig if unset or empty into release/1.20.x #14103

Job	Run time
conditional-skip / Check whether to skip build and tests	26s
get-envoy-versions / Determine supported Envoy versions	5s
get-go-version / Determine Go toolchain version	5s
Setup	3s
integration-test-with-deployer	2m 15s
Generate Envoy Job Matrices	3s
dev-build / build	38s
nomad-integration-test (v1.7.7)	2m 2s
compatibility-integration-test	11m 24s
nomad-integration-test (v1.6.10)	2m 11s
vault-integration-test (1.16.2)	2m 11s
envoy-integration-test (server, case-l7-intentions\|case-cross-peers-resolver-redirect-tcp\|case-cf...	7m 23s
vault-integration-test (1.15.6)	2m 21s
nomad-integration-test (v1.5.17)	1m 34s
envoy-integration-test (server, case-terminating-gateway-without-services\|case-api-gateway-http-t...	6m 15s
vault-integration-test (1.14.10)	2m 16s
envoy-integration-test (server, case-terminating-gateway-hostnames\|case-consul-exec\|case-multidc-...	6m 47s
envoy-integration-test (server, case-cfg-router-features)	2m 15s
envoy-integration-test (client, case-l7-intentions\|case-cross-peers-resolver-redirect-tcp\|case-cf...	7m 39s
envoy-integration-test (client, case-terminating-gateway-without-services\|case-api-gateway-http-t...	6m 11s
envoy-integration-test (client, case-terminating-gateway-hostnames\|case-consul-exec\|case-multidc-...	7m 11s
envoy-integration-test (client, case-cfg-router-features)	2m 20s
test-integrations-success	6s
	1h 13m 41s

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