Unmute ApmAgentSettingsIT (elastic#122865)

This was just muted shortly before the
[fix](elastic#122844) was
backported. Closes elastic#122546

Author: mosche

muted-tests.yml

@@ -474,5 +474,4 @@ tests:
 - class: org.elasticsearch.xpack.test.rest.XPackRestIT
   method: test {p0=snapshot/10_basic/Create a source only snapshot and then restore it}
   issue: https://github.com/elastic/elasticsearch/issues/122755
-- class: org.elasticsearch.telemetry.apm.ApmAgentSettingsIT
-  issue: https://github.com/elastic/elasticsearch/issues/122546
+