Have a hook update to add the default box shadow configs for old sites

Problem/Motivation

After updating to Bootstrap Styles 1.1.0
box_shadow: "bs-shadow-sm|Small\r\nbs-shadow|Regular\r\nbs-shadow-lg|Large"
But #3188559: Plugin: Shadow was committed around 1 year ago without a hook update!
https://git.drupalcode.org/project/bootstrap_styles/-/commit/35c0c005797...

Bootstrap Styles 1.1.0 was release 14 Jan 2023
But the #3188559: Plugin: Shadow was not listed in the release notes

Having issues when editing or saving old sections, when no default value was sat to the box_shadow .

Proposed resolution

• Have a hook update to add the new default config box_shadow: "bs-shadow-sm|Small\r\nbs-shadow|Regular\r\nbs-shadow-lg|Large" for old websites.

Remaining tasks

• MR/Patch
• Test updating from 1.0.3 to 1.1.0 in an old site with content and sections
• Review code

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A