Remove duplicate identity test variables (Azure#38370)

Author: benbp

sdk/identity/tests.yml

@@ -16,12 +16,6 @@ extends:
           PEM_CONTENTS: $(net-identity-spcert-pem)
           SNI_CONTENTS: $(net-identity-spcert-sni)
     EnvVars:
-      AZURE_IDENTITY_TEST_TENANTID: $(net-identity-tenantid)
-      AZURE_IDENTITY_TEST_USERNAME: $(net-identity-username)
-      AZURE_IDENTITY_TEST_PASSWORD: $(net-identity-password)
-      IDENTITY_SP_CLIENT_ID: $(net-identity-sp-clientid)
-      IDENTITY_SP_TENANT_ID: $(net-identity-sp-tenantid)
-      IDENTITY_SP_CLIENT_SECRET: $(net-identity-sp-clientsecret)
       IDENTITY_SP_CERT_PFX: $(Agent.TempDirectory)/test.pfx
       IDENTITY_SP_CERT_PEM: $(Agent.TempDirectory)/test.pem
       IDENTITY_SP_CERT_SNI: $(Agent.TempDirectory)/testsni.pfx