Loading an older bndb from inside a container fails with "attempt to write a readonly database"

[bpotchik]

Bug Description:
When a bndb is extracted from a container (e.g. a .zip) it is deserialized into SQLite in-memory with SQLITE_DESERIALIZE_READONLY. If the bndb is from an older Binary Ninja version that
requires a schema upgrade, UpdateSchema then tries to write to that read-only handle and the load aborts with attempt to write a readonly database. Direct on-disk loads of the same bndb upgrade and open fine. The failure is specific to the container-extracted path.

Steps To Reproduce:

1. Take an older bndb (e.g. one produced by Binary Ninja v1.0.730).
2. Place it inside a zip archive.
3. Open the zip in Binary Ninja so the container extraction path runs.

** Expected Behavior **
The bndb is upgraded in memory and opens normally, just like the on-disk case. Persistence to the original container is not required.

[bpotchik]

Fixed in 9674.