delete asset doesn't remove asset from lineage

[bsushmith]

Describe the bug
Using DELETE asset endpoint, doesn't delete asset from lineage repository. It only deletes from asset repository and discovery repository.

To Reproduce
Steps to reproduce the behavior:

1. Create Asset A
2. Create Asset B which has upstream/downstream relation with asset A so that it is part of asset A lineage.
3. Delete Asset B
4. Asset A would still have asset B in its lineage

Expected behavior
Deleted asset B should not be part of the lineage of asset A

Additional context
Tested version - v0.2.2. But the delete logic looks the same in the latest version also.