The directives that accept filenames as arguments must use Windows filenames instead of Unix ones. However, because Apache may interpret backslashes as an "escape character" sequence, you should consistently use forward slashes in path names, not backslashes. (Apache documentation: "Customizing Apache for Windows")
So try forward slashes:
DocumentRoot "C:/Program Files/Jenkins/jobs/Drupal_Test/workspace/app"
<Directory "C:/Program Files/Jenkins/jobs/Drupal_Test/workspace/app">
# ....