Remove test mute for OldRepositoryAccessIT testOldRepoAccess (#117845) (#117964)

This has been fixed with #117649 on "main" and the changes causing this
haven't been backported to 8.x. The test was muted due to occasional
timeouts that are unrelated that should have been fixed in the meantime.

(cherry picked from commit 7853e12)

# Conflicts:
#	muted-tests.yml

Co-authored-by: Christoph Büscher <[email protected]>

Author: piergm

muted-tests.yml

@@ -350,9 +350,6 @@ tests:
 - class: org.elasticsearch.xpack.searchablesnapshots.RetrySearchIntegTests
   method: testRetryPointInTime
   issue: https://github.com/elastic/elasticsearch/issues/117116
-- class: org.elasticsearch.oldrepos.OldRepositoryAccessIT
-  method: testOldRepoAccess
-  issue: https://github.com/elastic/elasticsearch/issues/115631
 - class: org.elasticsearch.xpack.inference.DefaultEndPointsIT
   method: testMultipleInferencesTriggeringDownloadAndDeploy
   issue: https://github.com/elastic/elasticsearch/issues/117208