Block plugin is missing config schema

This patch adds a config schema for the plugin to avoid config inspect errors about a missing schema

rakesh.regar → made their first commit to this issue’s fork.

Reviewing this!!

I was able to reproduce this issue!!
Before applying the patch, there was a missing schema warning for settings.show_cookies_settings_button when checked using the Config Inspector module.
After applying the patch and clearing cache, the warning is gone, and everything is working as expected..
Changes looks good to me thus moving this to RTBC.