*_history lines in extra-info descriptor DB entry contain parsed values twice

Consider the following object we get (by calling desc.getReadHistory()) when looking at the read_history of a relay:

{"line":"read-history 2024-06-10 17:36:37 (86400 s) 221658422272,236868623360,227962770432,248584955904,220272773120","historyEndMillis":1718040997000,"intervalLength":86400,"bandwidthValues":{"1717695397000":221658422272,"1717781797000":236868623360,"1717868197000":227962770432,"1717954597000":248584955904,"1718040997000":220272773120}}

That's the thing we store in the database and contains the same data parsed twice: once as we have it in the descriptor ("line") and once by having it more readily available (spelling out "historyEndMillis" and so on. It feels a bit overkill space-wise to have both of those data representations stored in the DB.