ESQL: Unmute and fix missing cabability in SubstituteRoundToTests

muted-tests.yml

@@ -436,9 +436,6 @@ tests:
 - class: org.elasticsearch.xpack.esql.qa.single_node.GenerativeForkIT
   method: test {csv-spec:inlinestats.MvMinMvExpand}
   issue: https://github.com/elastic/elasticsearch/issues/137679
-- class: org.elasticsearch.xpack.esql.optimizer.rules.physical.local.SubstituteRoundToTests
-  method: testSubqueryWithCountStarAndDateTrunc {default}
-  issue: https://github.com/elastic/elasticsearch/issues/138601
 - class: org.elasticsearch.xpack.ilm.TimeSeriesLifecycleActionsIT
   method: testWaitForSnapshot
   issue: https://github.com/elastic/elasticsearch/issues/138669

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/optimizer/rules/physical/local/SubstituteRoundToTests.java

@@ -16,6 +16,7 @@
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.index.query.RangeQueryBuilder;
 import org.elasticsearch.xpack.esql.EsqlTestUtils;
+import org.elasticsearch.xpack.esql.action.EsqlCapabilities;
 import org.elasticsearch.xpack.esql.core.expression.Alias;
 import org.elasticsearch.xpack.esql.core.expression.Attribute;
 import org.elasticsearch.xpack.esql.core.expression.Expression;
@@ -859,6 +860,7 @@ public void testForkWithStatsCountStarDateTrunc() {
     }
 
     public void testSubqueryWithCountStarAndDateTrunc() {
+        assumeTrue("requires subqueries in from", EsqlCapabilities.Cap.SUBQUERY_IN_FROM_COMMAND.isEnabled());
         String query = """
             from test, (from test | stats cnt = count(*) by x = date_trunc(1 day, date))
             | keep x, cnt, date