Fix mj-social-element when inline style is added

[Br1mbelle]

When inline style is added, the first social element is centered but the following are on the left side.

The TD tag of mj-social-element is not well closed and juice add closing tags and change the html code.

Tested with the following MJML :

<mjml>
  <mj-head>
    <mj-style inline="inline"></mj-style>
  </mj-head>
  <mj-body>
    <mj-section>
      <mj-column>
        <mj-social mode="horizontal">
          <mj-social-element name="facebook" href="https://mjml.io/">
            Facebook
          </mj-social-element>
          <mj-social-element name="google" href="https://mjml.io/">
            Google
          </mj-social-element>
          <mj-social-element  name="instagram" href="https://mjml.io/">
            Instagram
          </mj-social-element>
        </mj-social>
      </mj-column>
    </mj-section>
  </mj-body>
</mjml>

[kmcb777]

@Br1mbelle Hi, thanks for finding this 👍
The fix is ok for me

[kmcb777]

We first merge into next, not directly into master, so i'll close this one