Incorrect try except in `insert_advisory_v2`

[keshav-space]

insert_advisory_v2 should use AdvisoryV2.MultipleObjectsReturned

vulnerablecode/vulnerabilities/pipes/advisory.py

Line 334 in 4402d6e

except Advisory.MultipleObjectsReturned:

[Coolsheru2526]

@keshav-space can i start working on this issue and be assigned this issue.