VA: Fix duplicate vote bug with votes import

[jessemortenson]

VA vote events were failing to import with errors like:

INFO - [base] openstates.exceptions.DuplicateItemError: attempt to import data that would conflict with data already in the import: {'identifier': '', 'motion_text': 'Reported with amendments', 'motion_classification': [], 'start_date': '2024-01-31', 'result': 'pass', 'extras': {}, 'dedupe_key': 'H092024-01-311', 'legislative_session_id': UUID('27766658-dae9-4950-8565-ca0a88ea931e'), 'organization_id': 'ocd-organization/0c3daf42-2835-49cf-8f58-b1d771dae687', 'bill_id': 'ocd-bill/61eb4a36-d3f6-4855-a913-7f45613910e2', 'bill_action_id': UUID('37298987-68ef-4d79-99d8-6a8dec9fa5e2')} (already imported as Reported with amendments on HB 582 in Virginia 2025 Regular Session)
INFO - [base] obj1 sources: ["[https://lis.virginia.gov/vote-details/[{'VoteLegislationID':](https://lis.virginia.gov/vote-details/[%7B'VoteLegislationID':) 306230, 'LegislationID': 92156, 'LegislationNumber': 'HB582', 'Description': 'Public high schools; each school board to employ at least one career coach.                         ', 'VoteNumber': None, 'VoteItems': []}]/20251/H092024-01-311"]
INFO - [base] obj2 sources: ["[https://lis.virginia.gov/vote-details/[{'VoteLegislationID':](https://lis.virginia.gov/vote-details/[%7B'VoteLegislationID':) 306230, 'LegislationID': 92156, 'LegislationNumber': 'HB582', 'Description': 'Public high schools; each school board to employ at least one career coach.                         ', 'VoteNumber': None, 'VoteItems': []}]/20251/H092024-01-311"]

Looks like dedupe key used was not actually unique. Also fixes URL used as sources for votes.

[jessemortenson]

FYI @showerst - just in case I missed something in changing the logic around dedupe key or source here on Vote Events