fix: do not set normalized name for existing chats and contacts in a migration

[link2xt]

We got a report that application is not responding after update on Android and getting killed before it can start, suspected to be a slow SQL migration:
#7602

This change removes calculation of normalized names for existing chats and contacts added in
#7548
to exclude the possibility of this migration being slow. New chats and contacts will still get normalized names and all chats and contacts will get it when they are renamed.

[iequidoo]

It was instant for me, but i don't have thousands of contacts/chats. Maybe 10000 is too much. Anyway, fine to remove this code completely

[link2xt]

It was instant for me, but i don't have thousands of contacts/chats. Maybe 10000 is too much. Anyway, fine to remove this code completely

It could also be that the issue is imap migration, but we don't know because we don't have logs this early (see original issue). And the user has Fairphone 3 that apparently has slower eMMC storage than recent phones with UFS. I also have not found the data on actual throughput etc. of storage, everyone just states the storage size and standard.

[link2xt]

For the record, this did not solve the problem at least entirely, some other migration like maybe 140 still takes a lot of time with large database: #7602 (comment)
But let's keep this merged, it anyway saves some time.