new tskit release breaks something here

[petrelharp]

Running get_pop_ancestry with the beta release for tskit gets:

> anc = tspop.get_pop_ancestry(tss,census_time=2)
... 
Traceback (most recent call last):
  File "<python-input-7>", line 9, in <module>
    anc = tspop.get_pop_ancestry(tss,census_time=2)
  File "/home/peter/projects/tskit-dev/tsvenv/lib/python3.13/site-packages/tspop.py", line 22, in get_pop_ancestry
    pop_table = __replace_parents_with_pops(ts, census_nodes)
  File "/home/peter/projects/tskit-dev/tsvenv/lib/python3.13/site-packages/tspop.py", line 30, in __replace_parents_with_pops
    ancestor_table = ts.tables.link_ancestors(
                     ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/peter/projects/tskit-dev/tsvenv/lib/python3.13/site-packages/tskit/tables.py", line 4817, in __getattr__
    raise ImmutableTableError(
    ...<2 lines>...
    )
tskit.exceptions.ImmutableTableError: Cannot call link_ancestors() on immutable table collection. Use TreeSequence.dump_tables() for mutable copy.

See tskit-dev/tskit#3288 for what's going on here.

[hyanwong]

See tskit-dev/tskit#3312