Mute ydb/core/tablet_flat/ut TSharedPageCache.Compaction_BTreeIndex (#12863)

Author: maximyurchuk

.github/config/muted_ya.txt

@@ -60,6 +60,7 @@ ydb/core/mind/hive/ut THiveTest.TestHiveBalancerNodeRestarts
 ydb/core/persqueue/ut TPQTest.TestReadAndDeleteConsumer
 ydb/core/persqueue/ut [*/*] chunk chunk
 ydb/core/quoter/ut QuoterWithKesusTest.PrefetchCoefficient
+ydb/core/tablet_flat/ut TSharedPageCache.Compaction_BTreeIndex
 ydb/core/tx/datashard/ut_incremental_backup IncrementalBackup.ComplexRestoreBackupCollection+WithIncremental
 ydb/core/tx/schemeshard/ut_move_reboots TSchemeShardMoveRebootsTest.WithData
 ydb/core/tx/schemeshard/ut_move_reboots TSchemeShardMoveRebootsTest.WithDataAndPersistentPartitionStats