Remove policy MS.SHAREPOINT4.2v1 due to Microsoft update to custom scripting settings

[ahuynhMITRE]

🗣 Description

Microsoft is making updates to the custom scripting configuration options for Sharepoint and OneDrive. The purpose of this PR is to remove the SCB references to these settings and add the policy, date of removal, and rationale to the removedpolicies.md.

This would be useful because as Microsoft rolls out this update, users of ScubaGear will experience errors as a result of the missing setting. This allows the ScubaGear and the SCBs to be update to date with this setting deprecation.

💭 Motivation and context

This would be useful because as Microsoft rolls out this update, users of ScubaGear will experience errors as a result of the missing setting. This allows the ScubaGear and the SCBs to be update to date with this setting deprecation.

Closes #1399

🧪 Testing

N/A currently only an SCB update, code change will be in a follow-up issue and PR.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• PR targets the correct parent branch (e.g., main or release-name) for merge.
• Changes are limited to a single goal - eschew scope creep!
• Changes are sized such that they do not touch excessive number of files.
• Related issues these changes resolve are linked preferably via closing keywords.
• All relevant type-of-change labels added.
• All relevant project fields are set.
• All relevant repo and/or project documentation updated to reflect these changes.
• All relevant functional tests passed.
• All automated checks (e.g., linting, static analysis, unit/smoke tests) passed.

✅ Pre-merge checklist

• PR passed smoke test check.

• Feature branch has been rebased against changes from parent branch, as needed

  Use Rebase branch button below or use this reference to rebase from the command line.

• Resolved all merge conflicts on branch

• Notified merge coordinator that PR is ready for merge via comment mention

✅ Post-merge checklist

• Feature branch deleted after merge to clean up repository.
• Verified that all checks pass on parent branch (e.g., main or release-name) after merge.

[tkol2022]

I am good with the changes in this PR. Make sure that #1400 gets into the same release otherwise we would have a ScubaGear report that does not line up with the baseline. Also, check the Sharepoint admin portal and see if the setting for 4.2 has been removed from the user interface and drop a note in the issue connected to this PR for awareness.

[schrolla]

@ahuynhMITRE Recommend updating the PR title to reference the policy by ID rather than name and change to use imperative voice (i.e. Removal of -> Remove).

[mitchelbaker-cisa]

Removed duplicate wording; bolded Blocked to be consistent with configuration setting formatting across the baselines.

Suggested change

- _Removal rationale:_ Microsoft has noted that after November 2024 it will no longer be possible to prevent SharePoint in resetting custom script settings to its original value (disabled) for all sites. All references including the policy, implementation steps, and section, by direction of CISA and Microsoft, have been removed as the setting will be will be automatically reverted back to Blocked within 24 hour.

- _Removal rationale:_ Microsoft has noted that after November 2024 it will no longer be possible to prevent SharePoint in resetting custom script settings to its original value (disabled) for all sites. All references including the policy, implementation steps, and section, by direction of CISA and Microsoft, have been removed as the setting will be automatically reverted back to **Blocked** within 24 hours.