Add more logging and exception usage in committee services

src/main/java/org/eclipsefoundation/wg/resource/WorkingGroupsResource.java

@@ -112,8 +112,7 @@ public class WorkingGroupsResource {
         }
 
         WorkingGroupCommittee committee = wgService.getWGCommittee(alias, groupPrefix);
-
-        if (Objects.isNull(committee)) {
+        if (committee == null) {
             throw new BadRequestException(String.format("Invalid committee parameters: %s, %s", alias, groupPrefix));
         }