KIKIMR-20150: remove the test from the mute list (#726)

Author: eivanov89

.github/config/muted_test.txt

@@ -6,7 +6,6 @@ ydb-core-blobstorage-ut_blobstorage/VDiskAssimilation::Test
 ydb-core-tx-columnshard-ut_schema/TColumnShardTestSchema::ForgetAfterFail
 ydb-core-tx-columnshard-ut_schema/TColumnShardTestSchema::RebootForgetAfterFail
 ydb-core-kqp-ut-federated_query-generic/*
-ydb-core-client-ut/TClientTest::FollowerOfflineBoot
 ydb-library-yql-sql-pg-ut/PgSqlParsingAutoparam::AutoParamValues_DifferentTypes
 ydb-core-blobstorage-ut_blobstorage/[6/10]*
 ydb/core/blobstorage/ut_blobstorage/Defragmentation::DoesItWork