[Proofreading] Remove segment from list after merge

[hotzenklotz]

Context

After merging two segments with the proof reading tool there should only be one remaining entry in the "Segments Tab" after the operation. Instead the the merged segment's list entry remains as a Karteileiche. Any operation on it will crash WK.

Expected Behavior

There should only be one list entry.

Current Behavior

There are two list entries. Right-click removing the "remainder" entry will crash the segment's tab.

Steps to Reproduce the bug

• Cannot reproduce the bug anymore / needs deeper investigation.

1. Click on each segment individually with proof reading tool
2. Merge two segments
3. Now you have two segments

Your Environment for bug

• Browser name and version: e.g. Chrome 116
• Operating System and version: e.g. MacOS
• Version of WEBKNOSSOS (Release or Commit): 24599
• Specific to long-running jobs (set jobsEnabled=true in application.conf)
• Specific to webknossos.org (set isDemoInstance=true in application.conf)