Corrected type hints in estimator classes and add tqdm to dev dependencies

[f-allian]

This pull request primarily focuses on correcting type annotations in several estimator classes and updating development dependencies. The changes improve code clarity and type safety by using the correct syntax for Python type hints.

Type annotation fixes:

• Standardized the type annotation syntax for effect_modifiers from dict[Type:Type] to dict[Type, Type] in the following files:
  • causal_testing/estimation/abstract_estimator.py (effect_modifiers: dict[str, Any])
  • causal_testing/estimation/abstract_regression_estimator.py (effect_modifiers: dict[Variable, Any])
  • causal_testing/estimation/cubic_spline_estimator.py (effect_modifiers: dict[Variable, Any])
  • causal_testing/estimation/linear_regression_estimator.py (effect_modifiers: dict[Variable, Any])
  • causal_testing/estimation/experimental_estimator.py (adjustment_set and effect_modifiers: dict[str, Any])

Dependency updates:

• Added tqdm to the dev dependencies in pyproject.toml to support progress bar functionality during development.

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	33		0	0.92s
✅ PYTHON	pylint	33		0	5.49s

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.27%. Comparing base (20aace7) to head (4f7b245).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #357   +/-   ##
=======================================
  Coverage   96.27%   96.27%           
=======================================
  Files          28       28           
  Lines        1584     1584           
=======================================
  Hits         1525     1525           
  Misses         59       59           

Files with missing lines	Coverage Δ
causal_testing/estimation/abstract_estimator.py	100.00% <ø> (ø)
...esting/estimation/abstract_regression_estimator.py	95.83% <ø> (ø)
...ausal_testing/estimation/cubic_spline_estimator.py	96.66% <ø> (ø)
...ausal_testing/estimation/experimental_estimator.py	100.00% <ø> (ø)
..._testing/estimation/linear_regression_estimator.py	100.00% <ø> (ø)

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