Potential fix for pull request finding

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

Author: greghuels

tracer/src/Datadog.Trace/FeatureFlags/SemVer.cs

@@ -25,7 +25,7 @@ public static bool TryParse(string version, out ParsedSemVer result)
     {
         result = default;
 
-        if (string.IsNullOrEmpty(version))
+        if (StringUtil.IsNullOrEmpty(version))
         {
             return false;
         }