Fixed `priorband_template.py` example

[gopaljigaur]

This pull request includes several changes to improve error handling and parameter validation in the package. The most important changes include adding more informative error messages and ensuring parameter bounds are correctly validated.

Error Handling Improvements:

• neps/optimizers/multi_fidelity/successive_halving.py: Added an error message to the assertion for the fidelity parameter to clarify when it is not set.

Parameter Validation:

• neps/search_spaces/hyperparameters/numerical.py: Added a check to raise a ValueError if the fidelity parameter bounds are less than or equal to zero when using a log scale.
• neps_examples/template/priorband_template.py: Changed the lower bound of the wd parameter to 1e-5 to ensure it is within a valid range.Add non-negative value check for fidelity parameter.

[gopaljigaur]

This pull request includes several changes to improve the handling of fidelity parameters and validation of YAML configurations. The most important changes involve adding validation checks, updating test configurations, and modifying default values.

Validation Improvements:

• Added a detailed assertion message for the fidelity parameter in __init__ method of neps/optimizers/multi_fidelity/successive_halving.py.
• Introduced a check to raise a ValueError if fidelity parameter bounds are less than or equal to zero in neps/search_spaces/hyperparameters/numerical.py.

Configuration Updates:

• Updated lower bound for wd parameter in neps_examples/template/priorband_template.py from 0 to 1e-5.
• Changed lower bound for param_int1 in tests/test_yaml_search_space/correct_config.yaml and tests/test_yaml_search_space/correct_config_including_types.yaml from -3 to 3. [1] [2]

Test Enhancements:

• Added a new test case test_incorrect_fidelity_parameter_bounds to validate fidelity parameter bounds in tests/test_yaml_search_space/test_search_space.py.
• Updated test configuration files to include new parameter bounds and types in tests/test_yaml_search_space/incorrect_fidelity_bounds_config.yaml.

[gopaljigaur]

@DaStoll @eddiebergman