Fix progress bar error for parallel executions

[Ig-dolci]

Description

ProgressBar is now being tested by adding it in parallel execution.

See the error:

Evaluating Adjoint ▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣▣ 401/401 [0:00:41]Traceback (most recent call last):
  File "/Users/ddolci/work/firedrake/simulations_worflows_did/fwi/circle_fwi.py", line 118, in <module>
Traceback (most recent call last):
  File "/Users/ddolci/work/firedrake/simulations_worflows_did/fwi/circle_fwi.py", line 118, in <module>
    J_hat.derivative()
    J_hat.derivative()
  File "/Users/ddolci/work/firedrake/src/firedrake/firedrake/adjoint/ensemble_reduced_functional.py", line 139, in derivative
  File "/Users/ddolci/work/firedrake/src/firedrake/firedrake/adjoint/ensemble_reduced_functional.py", line 139, in derivative
    dJdm_local = super(EnsembleReducedFunctional, self).derivative(adj_input=adj_input, options=options)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/reduced_functional.py", line 130, in derivative
    dJdm_local = super(EnsembleReducedFunctional, self).derivative(adj_input=adj_input, options=options)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/reduced_functional.py", line 130, in derivative
    derivatives = compute_gradient(self.functional,
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/drivers.py", line 30, in compute_gradient
    derivatives = compute_gradient(self.functional,
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/drivers.py", line 30, in compute_gradient
    tape.evaluate_adj(markings=True)
    tape.evaluate_adj(markings=True)
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/tape.py", line 339, in evaluate_adj
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/tape.py", line 339, in evaluate_adj
    self._checkpoint_manager.evaluate_adj(last_block, markings)
    self._checkpoint_manager.evaluate_adj(last_block, markings)
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/checkpointing.py", line 220, in evaluate_adj
  File "/Users/ddolci/work/firedrake/src/pyadjoint/pyadjoint/checkpointing.py", line 220, in evaluate_adj
    with self.tape.progress_bar("Evaluating Adjoint", max=self.total_timesteps) as progress_bar:
    with self.tape.progress_bar("Evaluating Adjoint", max=self.total_timesteps) as progress_bar:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: _NullProgressBar.__exit__() takes 1 positional argument but 4 were given
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: _NullProgressBar.__exit__() takes 1 positional argument but 4 were given

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake complex	8090 ran	6507 passed	1583 skipped	0 failed

[github-actions]

	Tests	Passed ✅	Skipped ⏭️	Failed ❌
Firedrake real	8096 ran	7310 passed	786 skipped	0 failed

[connorjward]

I think this will be fine if we re-run things now.