ESQL: Reenable test (#109490)

We disabled this test because it failed once but it wasn't reproducable
and the test logs didn't give us any hints of what happened. So this
reenables is. If we're lucky it'll fail again with useful logs. If we're
not lucky it'll never fail again and we'll blame cosmic rays.

Closes #109477

muted-tests.yml

@@ -62,9 +62,6 @@ tests:
 - class: org.elasticsearch.xpack.esql.expression.function.scalar.multivalue.MvAppendTests
   method: testEvaluateBlockWithoutNulls {TestCase=<cartesian_shape>, <cartesian_shape>}
   issue: https://github.com/elastic/elasticsearch/issues/109409
-- class: "org.elasticsearch.xpack.esql.qa.multi_node.EsqlClientYamlIT"
-  issue: "https://github.com/elastic/elasticsearch/issues/109477"
-  method: "test {p0=esql/150_lookup/multivalued keys}"
 - class: "org.elasticsearch.smoketest.DocsClientYamlTestSuiteIT"
   issue: "https://github.com/elastic/elasticsearch/issues/109478"
   method: "test {yaml=reference/esql/processing-commands/lookup/line_31}"