Avoid uninitialized dnf's history.sqlite

[marmarek]

Do not leave uninitialized history.sqlite in the template. When it
doesn't exist, dnf will create it with the proper structure. But when it
exists, it will expect its tables to exist already. Empty sqlite file
(just headers) breaks this assumption resulting in update errors like:

fedora-41-xfce:out: Refreshing package info
fedora-41-xfce:err: History database is not writable: SQLite error on "/var/lib/dnf/history.sqlite": Executing an SQL statement failed: no such table: config
fedora-41-xfce:err: History database is not writable: SQLite error on "/var/lib/dnf/history.sqlite": Executing an SQL statement failed: no such table: config
fedora-41-xfce:err: SQLite error on "/var/lib/dnf/history.sqlite": Executing an SQL statement failed: no such table: config

The history.sqlite with just headers has 4096 bytes. Properly
initialized one over 100k. To be on the conservative side, set the
threshold at 8k - if it's smaller - remove it (together with sqlite's
side files).

Fixes QubesOS/qubes-issues#9744

[alimirjamali]

Sadly we do not have sqlite3 binary by default to dump the database schema and check for the tables (e.g. config).

[marmarek]

Yes, I considered this option (including requiring selite3 to be installed), but since the size difference is significant, the current check should also work.