Remove Unit testsuite from phpunit.xml since tests/Unit directory doesn't exist

Co-authored-by: srtfisher <346399+srtfisher@users.noreply.github.com>

Author: Copilot

phpunit.xml

@@ -11,9 +11,6 @@
     <testsuite name="Feature">
       <directory suffix=".php">tests/Feature</directory>
     </testsuite>
-    <testsuite name="Unit">
-      <directory suffix=".php">tests/Unit</directory>
-    </testsuite>
   </testsuites>
   <php>
     <ini name="error_reporting" value="-1" />