Fix CI error when plugin is already named correctly

- Check if plugin file is already named intellij-plugin.zip before renaming
- Use mv instead of cp to avoid duplicate files
- Prevents "are the same file" error in CI

Co-authored-by: Mte90 <403283+Mte90@users.noreply.github.com>

Author: Copilot

.github/workflows/kotlin-ci.yml

@@ -77,8 +77,8 @@ jobs:
         run: |
           cd ide-plugins/build/distributions
           PLUGIN_FILE=$(ls *.zip | head -n 1)
-          if [ -n "$PLUGIN_FILE" ]; then
-            cp "$PLUGIN_FILE" intellij-plugin.zip
+          if [ -n "$PLUGIN_FILE" ] && [ "$PLUGIN_FILE" != "intellij-plugin.zip" ]; then
+            mv "$PLUGIN_FILE" intellij-plugin.zip
           fi
         if: success()