fix: update single select field display logic in markdown views

Author: tanhongit

resources/views/md/comment.blade.php

@@ -1,7 +1,7 @@
 @php
     $fieldName = $payload['projects_v2_item']['field_name'];
-    $fromValue = $payload['from']['name'] ?? 'Unknown';
-    $toValue = $payload['to']['name'] ?? 'Unknown';
+    $fromValue = $payload['from']['name'] ?? null;
+    $toValue = $payload['to']['name'] ?? null;
 @endphp
 @include(
     'github-project::md.field_types.' . $payload['projects_v2_item']['field_type'],

resources/views/md/field_types/single_select.blade.php

@@ -0,0 +1,5 @@
+@if($fromValue != null)
+**{{ $fieldName }}** has been changed from $${\color{{{ $payload['from']['color'] }}}{{ $fromValue }}$$ to $${\color{{{ $payload['to']['color'] }}}{{ $toValue }}$$.
+@else
+**{{ $fieldName }}** has been set to $${\color{{{ $payload['to']['color'] }}}{{ $toValue }}$$.
+@endif