Remove legacy filter that causes undesired double spacing

[tonytaylor]

Description

This is a follow-up to #13550.

We found that there are multiple filters (Limit allowed HTML tags and correct faulty HTML & Correct faulty and chopped off HTML) that appear to put break tags into a state where they fail a check to not add an extra break tag. This issue may be resolved by patching the rule that seeks out the break tags to match them in their post-processed state.

Acceptance Criteria

• Content in the Rich Text Limited editor does not create break <br> tags where there's a <br> + \n (Return)

Team

Please check the team(s) that will do this work.

• CMS Team
• Public Websites
• Facilities
• Accelerated Publishing

[tonytaylor]

Update

TL;DR - This issue is caused by a 5-year old patch addressing a separate issue. Removal of the patch should resolve this matter.

I was vetting this issue out on a vanilla D10 install and could not replicate the problem. I soon found that our code is doing something different than that of core and recently ran it by @ndouglas. He quickly identified that we're already patching that code to address a separate issue improper new line/carriage return conversion, which was addressed last year with Html::transformRootRelativeUrlsToAbsolute() replaces "\r\n" with " \n". Currently testing our D10 candidate build without the patch and all appears well. cc: @BerniXiongA6 @maortiz-27-80 @EWashb