Pay stub opens as download instead of preview

Clicking a student's pay stub icon on the WBL dashboard should open the pay stub image in a new tab as it did before. It now sends the file directly to downloads instead of displaying it. This happens in Google Chrome and persists after standard troubleshooting steps. The pay stub images are stored as JPG files, and some are PNG rather than PDF, which may be related to the changed behavior. Restore the previous open-in-new-tab behavior for pay stub images.