PPHA-627: Asbestos page updates (#404)

# What is the change?

Updates to Asbestos at work page

# Why are we making this change?

Making the Asbestos at work page match the current designs.

Author: jamiefalcus

lung_cancer_screening/questions/jinja2/asbestos_exposure.jinja

@@ -19,7 +19,9 @@
     <li>electricians</li>
   </ul>
 
-  <p>You may have come into contact with asbestos from existing asbestos-containing materials in buildings and products. If they are intact or undamaged, they pose very little risk.</p>
+  <h2 class="nhsuk-heading-m">If you did not work with asbestos but think you might have been exposed</h2>
+
+  <p>You might know there was asbestos in buildings you have spent time in, or products you have used. But if the asbestos was not damaged, the risk to your health is very low.</p>
 
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