Enable CompactionScanner for flushes and minor compaction

Phoenix TTL is currently used for major compaction only. When max lookback is enabled on a table, PhoenixTTL leads to retaining all cell versions until the next major compaction. This improvement is for enabling Phoenix TTL, more specifically CompactionScanner, for flushes and minor compaction to remove the live or deleted cell versions beyond the max lookback window during flushes and minor compactions.