&nbsp; in Alt <IMG> not pull through on invalid character alt check

[YodaSpow]

Bug
  in Alt not pull through on invalid character alt check

Link
https://litmus.com/checklist/tests/12693206/download.html
https://litmus.com/checklist/tests/12693195/download.html

Line: 543

                            <tr>
                              <td valign="top" align="left"><a href="https://www.currys.co.uk/gbuk/search-keywords/xx_xx_xx_xx_xx/-1_in_20-/1_30/relevance-desc/xx-criteria.html?<%@ include view='dixDIXtrackingCPCW1' %>~SEG~FLO~2NOM2~<%@ include view='dixDIXtrackingCPCW2' %>" _label="2NOM2_FLO"><img align="left" width="308" height="196" src="https://currys-ssl.cdn.dixons.com/css/themes/email/2018-2019/wk43/PaydayDeals/SpringBNR07.jpg" alt=" Get your vacuum cleaner for&nbsp;free" border="0" class="dw" style="display:block; border:1px solid #1d428a;" /></a></td>
                            </tr>