ESQL: Fix test by add excluding capability (elastic#129202)

Closes elastic#129078
Closes elastic#129082

Author: bpintea

muted-tests.yml

@@ -496,12 +496,6 @@ tests:
 - class: org.elasticsearch.packaging.test.DockerTests
   method: test073RunEsAsDifferentUserAndGroupWithoutBindMounting
   issue: https://github.com/elastic/elasticsearch/issues/128996
-- class: org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT
-  method: test {lookup-join.LookupJoinOnTimeSeriesIndex ASYNC}
-  issue: https://github.com/elastic/elasticsearch/issues/129078
-- class: org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT
-  method: test {lookup-join.LookupJoinOnTimeSeriesIndex SYNC}
-  issue: https://github.com/elastic/elasticsearch/issues/129082
 - class: org.elasticsearch.upgrades.UpgradeClusterClientYamlTestSuiteIT
   method: test {p0=upgraded_cluster/70_ilm/Test Lifecycle Still There And Indices Are Still Managed}
   issue: https://github.com/elastic/elasticsearch/issues/129097

x-pack/plugin/esql/qa/testFixtures/src/main/resources/lookup-join.csv-spec

@@ -4587,6 +4587,7 @@ emp_no:integer | language_code:integer | language_name:keyword
 
 lookupJoinOnTimeSeriesIndex
 required_capability: join_lookup_v12
+required_capability: lookup_join_on_mixed_numeric_fields
 
 FROM k8s
 | RENAME network.bytes_in AS language_code