Uninstalling module deletes blocks with config present

Problem/Motivation

When uninstalling this module, it deletes any blocks which have the module's config present (even if it is empty).

Steps to reproduce

1. Install the module
2. Create a block and set a "not node type" or "not taxonomy type" condition and save
3. Edit an existing block, don't change any conditions and save (thus adding config)
4. Uninstall the module

Proposed resolution

Take inspiration from the "Block Visibility Groups" module (#2880373) and remove the conditions on the blocks on uninstall so the blocks don't get deleted.

Remaining tasks

Add uninstall functions to Block Visibility Conditions module and Block Visibility Conditions Commerce submodule.