Remove outdated file from skill (#11324)

Remove outdated file from skill

Co-authored-by: sarah.chen <sarah.chen@datadoghq.com>

Author: sarahchen6

.claude/skills/migrate-groovy-to-java/SKILL.md

@@ -12,7 +12,6 @@ Migrate test Groovy files to Java using JUnit 5
 2. Convert Groovy files to Java using JUnit 5
 3. Make sure the tests are still passing after migration and that the test count has not changed
 4. Remove Groovy files
-5. Add the migrated module path(s) to `.github/g2j-migrated-modules.txt`
 
 When converting Groovy code to Java code, make sure that:
 - The Java code generated is compatible with JDK 8