There is, under your notification preferences, however a lot of users are reporting the setting isn't working.
My eBay > Settings > Notifications
At least one user said when they turned notifications off, deleted app / rebooted phone / reinstalled app, then turned notifications back on and re-set their preferences that fixed the issue. So if they're really bugging you I suggest trying that.
If it doesn't work, submit a tech report - it's fast and easy and eBay does review these reports. The more people reporting, the higher priority the issue will get in the fix queue.
Options through the app:
1. Shake your device while the app is open and that will trigger the option for you to file a tech report or submit feedback on product features.
2. Anywhere you see the three dots or the ? you can tap on that to file a report. Screenshot below.
