chore: separate SDK OTEL test suite from custom formatters

Author: matiasperrone

phpunit.xml

@@ -14,9 +14,13 @@
       <exclude>./tests/OpenTelemetry/</exclude>
       <exclude>./tests/TestCase.php</exclude>
     </testsuite>
-    <testsuite name="OTEL">
+    <testsuite name="OTEL Functionality Test Suite">
       <directory>./tests/OpenTelemetry/</directory>
       <exclude>./tests/OpenTelemetry/ExampleTest.php</exclude>
+      <exclude>./tests/OpenTelemetry/Formatters</exclude>
+    </testsuite>
+    <testsuite name="OTEL Custom Formatters Test Suite">
+      <directory>./tests/OpenTelemetry/Formatters/</directory>
     </testsuite>
   </testsuites>
   <php>