[EntBackup] range.json - seqno of "current" is out of sync for intermediate merges

5.0.0-3078 - Steps followed:

1. Config a backup repo
2. Take 3 incr backups with parallel crud ops - copy the range.json files - (range.json, range1.json range2.json)
3. Stop ops - do a cluster operation - either a rebalance or a failover
4. Take 2 incr backups with parallel crud ops - copy range.json filed (range3.json, range4.json)
5. Merge all the backups - copy json file (range5.json)
6. Expected: range4.json's current seqno should match range5.json's current seqno - but they don't match
7. Repeat steps 1 - 5 - copying range.json files - range6.json, range7.json, range8.json, range9. json, range10.json, range 11.json
8. Expected: range10.json's current seqno should match range11.json's current seqno - but they don't match
9. Merge the backups from step 5 and step 7 - copy json file - range12.json
10. Expected: range11.json's current seqno should match range12.json's current seqno - here they match

Attaching all files with backup logs