fix weird flake in integration tests with sqlite

[zzstoatzz]

Bug summary

see https://github.com/PrefectHQ/prefect/actions/runs/13191059627/job/36823978425#step:3:2242

  File "/usr/local/lib/python3.9/site-packages/prefect/server/database/_migrations/env.py", line 159, in do_run_migrations
    context.run_migrations()
  File "<string>", line 8, in run_migrations
  File "/usr/local/lib/python3.9/site-packages/alembic/runtime/environment.py", line 946, in run_migrations
    self.get_context().run_migrations(**kw)
  File "/usr/local/lib/python3.9/site-packages/alembic/runtime/migration.py", line 611, in run_migrations
    for step in self._migrations_fn(heads, self):
  File "/usr/local/lib/python3.9/site-packages/alembic/command.py", line 442, in downgrade
    return script._downgrade_revs(revision, rev)
  File "/usr/local/lib/python3.9/site-packages/alembic/script/base.py", line 476, in _downgrade_revs
    return [
  File "/usr/local/lib/python3.9/site-packages/alembic/script/base.py", line 476, in <listcomp>
    return [
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 814, in iterate_revisions
    revisions, heads = fn(
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 1339, in _collect_downgrade_revisions
    branch_label, target_revision = self._parse_downgrade_target(
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 1211, in _parse_downgrade_target
    return branch_label, self.get_revision(symbol)
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 584, in get_revision
    resolved_id, branch_label = self._resolve_revision_number(id_)
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 768, in _resolve_revision_number
    self._revision_map
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 1145, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "/usr/local/lib/python3.9/site-packages/alembic/script/revision.py", line 245, in _revision_map
    down_revision = map_[downrev]
KeyError: '354f1ede7e9f'

Version info

main

Additional context

No response

[cicdw]

I was just looking at this!! Yea it seems to have cropped up consistently.

[cicdw]

Doesn't always happen on older versions of sqlite: https://github.com/PrefectHQ/prefect/actions/runs/13203592361/job/36861326261?pr=17033

[cicdw]

This is still very much alive, my proposed fix didn't change anything