Save As drops all previous snapshots

Version and Platform (required):

• Binary Ninja Version: 3.5.4526
• OS: macOS
• OS Version: 12.6
• CPU Architecture: M1

Bug Description:
When I open a BNDB and later choose to "save as" to a new name, the created bndb has only the latest snapshot in its database. While this might be intentional, it was certainly not expected behavior. The currently open tab that you just saved still contains all the snapshots, and you only notice they are missing if you open the new bndb.

Steps To Reproduce:
Please provide all steps required to reproduce the behavior:

1. Enable database plugin
2. Open bndb
3. Open database pane and see snapshots
4. Save As to new name
5. Open new saved bndb
6. Open database pane and see only 2 snapshots

Expected Behavior:
I expected "save as" to create a full copy of the analysis database with all the snapshots.

Additional Information:
If this is not intended behavior we should make it more clear that this is what is going to happen.

Start by reproducing the issue with the database plugin: open a BNDB, inspect its snapshots in the database pane, use Save As, and reopen the new file. Trace the Save As and database-plugin entry points involved; done means the new BNDB retains all snapshots, or the behavior is clearly documented if it is intentional.