Create shapefile layer: allow to create Bool fields

[rouault]

Fixes #60324

[agiudiceandrea]

Does this actually fixes #60324?

I no longer have the option to force the "checked" state to "T" or the "unchecked" state to "F".
As a result, my existing display rules based on "T" and "F" no longer work.
...
I would expect the ability to customize the boolean field mapping (e.g., "checked" = "T", "unchecked" = "F") in QGIS 3.34.14, as it was possible in 3.34.4.

[rouault]

Does this actually fixes #60327?

probably not.

[github-actions]

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(Built from commit 6b2bc16)

[nyalldawson]

@agiudiceandrea i don't think #60324 is fixable. Users just need to adapt to the new capabilities.