fix(mdxish): normalize spacing for blank-line-split table tags

[eaglethrost]

🎫 RM-16757

🎯 What does this PR do?

Fixes a case where <Table> cells that contains HTML tags where the opener & closer tags are not alone in their lines and have text before them.

Note: the root cause isn't what the ticket describes (HTML whitespace entities on tag lines). It's our normalizeTagSpacing symmetry check, when opener and closer are both attached to text but a blank line splits them into separate paragraphs, mdxjs can't match the pair. We now treat that case as needing normalization too.

🧪 QA tips

• See the new test in __tests__/transformers/mdxish-tables.test.ts — a <Table> with a <div> whose contents span a blank line now parses to a single table node.
• Try the following markdown in the editor, it should render as a single table:

<Table>
  <thead>
    <tr><th>Icon</th><th>Status</th></tr>
  </thead>
  <tbody>
    <tr>
      <td>
        <div style="text-align:center; color:red">hi

        there</div>
      </td>
      <td>**Enabled**. The device is active.</td>
    </tr>
  </tbody>
</Table>

[kevinports]

Lgtm