Fix flaky test reporter failing with long failure message (#14141)

Author: laurit

test-report/src/main/java/io/opentelemetry/instrumentation/testreport/FlakyTestReporter.java

@@ -277,7 +277,8 @@ private void report(String accessKey, String buildScanUrl, String jobUrl) throws
       row.add(flakyTest.testName);
       row.add(buildScanUrl);
       row.add(jobUrl);
-      row.add(flakyTest.message);
+      // there is a limit of 50000 characters in a single cell
+      row.add(abbreviate(flakyTest.message, 10000));
       data.add(row);
     }
 
@@ -291,6 +292,14 @@ private void report(String accessKey, String buildScanUrl, String jobUrl) throws
         .execute();
   }
 
+  private static String abbreviate(String text, int maxLength) {
+    if (text.length() > maxLength) {
+      return text.substring(0, maxLength - 3) + "...";
+    }
+
+    return text;
+  }
+
   public static void main(String... args) throws Exception {
     String path = System.getProperty("scanPath");
     if (path == null) {