Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: smutniak

src/main/java/org/tdl/vireo/model/repo/impl/SubmissionRepoImpl.java

@@ -796,9 +796,7 @@ public int compare(SubmissionListColumn svc1, SubmissionListColumn svc2) {
                     for (String filterString : submissionListColumn.getFilters()) {
                         sqlBuilder = new StringBuilder();
 
-                        if (filterString == null) {
-                            sqlBuilder.append("a.email IS NULL");
-                        } else if (filterString.equalsIgnoreCase("null")) {
+                        if (filterString == null || "null".equalsIgnoreCase(filterString)) {
                             sqlBuilder.append("a.email IS NULL");
                         } else if (submissionListColumn.getExactMatch()) {
                             sqlBuilder.append("a.email = '").append(filterString).append("'");