Antijoin panics using left_on/right_on

[Vince7778]

Running an antijoin on two dataframes causes a panic if using the left_on and right_on arguments. This does not occur if regular on is used, or if the join is not an antijoin.

Example:

>>> df1 = daft.from_pydict({"a": [1, 2, 3, 4]})
>>> df2 = daft.from_pydict({"b": [3, 2]})
>>> df = df1.join(df2, left_on="a", right_on="b", how="anti")
>>> df.show()
thread '' panicked at src/daft-plan/src/physical_planner/translate.rs:509:67:
called `Result::unwrap()` on an `Err` value: FieldNotFound("Column \"b\" not found in schema: [\"a\"]")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/conor/Documents/Programming/daft/Daft/daft/api_annotations.py", line 26, in _wrap
    return timed_method(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/conor/Documents/Programming/daft/Daft/daft/analytics.py", line 185, in tracked_method
    return method(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/conor/Documents/Programming/daft/Daft/daft/dataframe/dataframe.py", line 1874, in show
    dataframe_display = self._construct_show_display(n)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/conor/Documents/Programming/daft/Daft/daft/dataframe/dataframe.py", line 1831, in _construct_show_display
    for table in get_context().runner().run_iter_tables(builder, results_buffer_size=1):
  File "/Users/conor/Documents/Programming/daft/Daft/daft/runners/pyrunner.py", line 198, in run_iter_tables
    for result in self.run_iter(builder, results_buffer_size=results_buffer_size):
  File "/Users/conor/Documents/Programming/daft/Daft/daft/runners/pyrunner.py", line 186, in run_iter
    plan_scheduler = builder.to_physical_plan_scheduler(daft_execution_config)
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/conor/Documents/Programming/daft/Daft/daft/logical/builder.py", line 47, in to_physical_plan_scheduler
    return PhysicalPlanScheduler.from_logical_plan_builder(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/conor/Documents/Programming/daft/Daft/daft/plan_scheduler/physical_plan_scheduler.py", line 35, in from_logical_plan_builder
    scheduler = _PhysicalPlanScheduler.from_logical_plan_builder(builder._builder, daft_execution_config)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pyo3_runtime.PanicException: called `Result::unwrap()` on an `Err` value: FieldNotFound("Column \"b\" not found in schema: [\"a\"]")

Expected output:

>>> df.show()
╭───────╮
│ a     │
│ ---   │
│ Int64 │
╞═══════╡
│ 1     │
├╌╌╌╌╌╌╌┤
│ 4     │
╰───────╯