Disable SLM history in docs tests

Author: nielsbauman

docs/build.gradle

@@ -130,8 +130,9 @@ testClusters.matching { it.name == "yamlRestTest"}.configureEach {
   setting 'xpack.security.enabled', 'true'
   setting 'xpack.security.authc.api_key.enabled', 'true'
   setting 'xpack.security.authc.token.enabled', 'true'
-  // disable the ILM history for doc tests to avoid potential lingering tasks that'd cause test flakiness
+  // disable the ILM and SLM history for doc tests to avoid potential lingering tasks that'd cause test flakiness
   setting 'indices.lifecycle.history_index_enabled', 'false'
+  setting 'slm.history_index_enabled', 'false'
   setting 'xpack.license.self_generated.type', 'trial'
   setting 'xpack.security.authc.realms.file.file.order', '0'
   setting 'xpack.security.authc.realms.native.native.order', '1'