Fix AttributeError in __is_bool Method for Non-String Data

[ihkao]

This PR addresses an issue in the __is_bool method within the EDA component. Previously, the method attempted to call .lower() and .strip() on all elements of the unique_vals array without checking their data types. This behavior caused an AttributeError when the array contained non-string data types, such as floats. The error is illustrated below:

sorted_unique_vals = sorted([_.lower().strip() for _ in unique_vals])
                                 ^^^^^^^
AttributeError: 'float' object has no attribute 'lower'

Modifications:

• Added a check to ensure that all elements in unique_vals are strings before proceeding with the .lower() and .strip() operations.
• This change prevents the AttributeError by skipping the lowercasing and stripping process for non-string elements, thus ensuring that the method can handle arrays with mixed data types gracefully.

Impact:

• The fix enhances the robustness of the __is_bool function by allowing it to handle a wider range of input types without failing.
• It ensures that the method behaves as expected even when encountering data types other than strings, thereby improving the overall data processing reliability in the EDA component.