fix matrix input email format issue (#562)

Author: madassdev

api/resources/views/mail/form/submission-notification.blade.php

@@ -16,7 +16,11 @@
 <a href="{{$link['signed_url']}}">{{$link['label']}}</a> <br/>
 @endforeach
 @else
-{!! is_array($field['value'])?implode(',',$field['value']):nl2br(e($field['value']))!!}
+@if($field['type'] == 'matrix')
+{!! nl2br(e($field['value'])) !!}
+@else
+{!! is_array($field['value'])?implode(',',$field['value']):$field['value']!!}
+@endif
 @endif
 @endif
 @endforeach