fix: update PR branch handling to fetch latest changes from remote

Author: linconvidal

.github/workflows/pr-preprod-tests.yaml

@@ -24,8 +24,12 @@ jobs:
         run: |
           cd /home/integration/git/cardano-rosetta-java
 
+          # Fetch latest from remote
+          git fetch origin
+
           # Clean up any existing PR branch and switch to main first
           git checkout main || git checkout develop
+          git pull origin main || git pull origin develop
           git branch -D pr-${{ github.event.pull_request.number }} 2>/dev/null || true
 
           # Fetch and checkout the PR