pgvector: Fix DropTable Function

[mehulmshah]

Overview

See issue #440. DropTables() returns an error:

ERROR: cannot drop table "Collections" because other objects depend on it (SQLSTATE 2BP01)

Switched the order to drop the s.embeddingTableName Table first, and then the s.collectionTableName Table.

PR Checklist

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[tmc]

Hmm this really should be covered by a test, but LGTM. Thanks for your contribution.

If you have the time could you add a test that exercises this?

[mehulmshah]

Hmm this really should be covered by a test, but LGTM. Thanks for your contribution.

If you have the time could you add a test that exercises this?

Agreed. Sure thing, I'll find some time this month to add a test case for this. Also, thoughts on adding more functionality around ability to delete embeddings / collections by ID or other field(besides the preDelete function)?