usager/dossiers: the link to the dossier is present:

- in the 'N° de dossier' column for mouse users and screen reader users.
- in the 'Démarche' column for mouse users, screen reader users and keyboard users.
Also added a sr-only class for text which should be read by screen-readers but not visible or accessible to other users

app/assets/stylesheets/new_design/dossiers_table.scss

@@ -67,6 +67,7 @@
     .label {
       width: 110px;
       text-align: center;
+      margin: 0 4px;
     }
   }
 
@@ -84,3 +85,16 @@
     width: 200px;
   }
 }
+
+.sr-only {
+  position: absolute;
+  width: 1px;
+  height: 1px;
+  opacity: 0;
+  padding: 0;
+  margin: -1px;
+  overflow: hidden;
+  clip: rect(0, 0, 0, 0);
+  white-space: nowrap;
+  border: none;
+}