[BUG] Adapter dispatch implementation

[DVAlexHiggs]

At this current time, the extension capability of dbtvault is causing errors.

When attempting to override dbtvault macros using the adapter_packages variable, dbtvault will complain that you are not overriding other macros; in other words, dbtvault does not fall back to its own implementation.

This has already been fixed internally and the fix will be in the next release.