Toolbar button is enabled by default on load

Problem/Motivation

CKEditor5 related - Usability is hampered by the blocks are being shown by default, on loading the content edit page, and on switching the Text formats for the CKEditor5 field. This was also not the behavior in CKEditor4+ of the same tool.

Steps to reproduce

• Install the module at version 1.3 or greater
• Enable for CKEditor5 Text input format, by adding it to the CKEditor5 toolbar.
• Edit content, and either load the edit page using the Text Format with CKEditor5, or switch to the CKEditor5 input format.

Proposed resolution

Either disable by default, both on loading the content to edit in CKEditor5, or introduce a setting for the tool, enabling the admin to toggle whether or not the 'Show Blocks' is to be enabled by default on load.