Indented List Items breaking all parent list items

[jamesosborne]

When adding an ordered list to the support forums, and then a sublist (by indenting child items), all following parent list items are misformatted and changed to unordered lists (top level)

This is easily to replicate, as a list item with step 1 and 2. Within Step 1, add some substeps, by indenting them (ie. Step 1.1 and 1.2). After doing so, only step 1 will be ordered.

[dd32]

This is a hold-over from the pre-block-editor, where we had to correct list item HTML often due to invalid syntax being posted.

See #20

I'll try disabling this for the Block Editor posts, as invalid HTML should be a thing of the past.

[dd32]

In 13635:

Support Forums: Don't apply the <li> improper HTML fixes to block content.

With support forum posts being written with the block editor, invalid HTML is much less likely now.

This tries removing the list item fixes from block posts.

See #20.
Fixes #7618.