Mute org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT test {p0=search.vectors/42_knn_search_int4_flat/Vector similarity with filter only} elastic#121412

Author: elasticsearchmachine

muted-tests.yml

@@ -507,3 +507,6 @@ tests:
 - class: org.elasticsearch.xpack.security.profile.ProfileIntegTests
   method: testSuggestProfileWithData
   issue: https://github.com/elastic/elasticsearch/issues/121258
+- class: org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT
+  method: test {p0=search.vectors/42_knn_search_int4_flat/Vector similarity with filter only}
+  issue: https://github.com/elastic/elasticsearch/issues/121412