Views: snapshot to skip ephermeral tables

[Shubham8287]

Description of Changes.

fixes #3715

The patch makes snapshots to skip ephemeral tables.

API and ABI breaking changes

NA

Expected complexity level and risk

1

Testing

[joshua-spacetime]

Could you add a test that previously would have snapshotted a view table before you merge?

[joshua-spacetime]

We sometimes see failures for test_view_tables_are_ephemeral like this one here. I believe this is due to the fact that we're currently snapshotting ephemeral tables (before this fix). Do you concur @Shubham8287?

[Shubham8287]

yeah, as per logs, It looks like due to snapshot, I wasn't aware this test can do snapshotting:

[INFO  spacetimedb::db::relational_db] [0000000000000000000000000000000000000000000000000000000000000000] DATABASE: durable_tx_offset is Some(3)
[INFO  spacetimedb::db::relational_db] [0000000000000000000000000000000000000000000000000000000000000000] DATABASE: restoring snapshot of tx_offset 3
[INFO  spacetimedb::db::relational_db] [0000000000000000000000000000000000000000000000000000000000000000] DATABASE: read snapshot of tx_offset 3 in 4.710688ms
[INFO  spacetimedb::db::relational_db] [0000000000000000000000000000000000000000000000000000000000000000] DATABASE: restored from snapshot of tx_offset 3 in 169.677µs
[INFO  spacetimedb::db::relational_db] [0000000000000000000000000000000000000000000000000000000000000000] DATABASE: applying transaction history...
[DEBUG spacetimedb_co

[joshua-spacetime]

Could you add a test that previously would have snapshotted a view table before you merge?

If we want to test with views specifically this would have to be a smoketest, but we can't control snapshotting from a smoketest. So I'm fine if you just want to use test_view_tables_are_ephemeral as a suitable regression test. It definitely shouldn't be flaky anymore after this change lands.