6558/bugfix/fix 50 edition merging bug

[mheiman]

Closes #6558

Addresses the problem of bad merges when the MergeUI doesn't retrieve all of the editions for a work.

Technical

• Increases the limit for retrieved editions from 50 to 200
• Identifies any works (other than the primary work) where the number of editions retrieved is less than the total number of editions and blocks the merge if that condition exists.

Testing

Try this merge: https://testing.openlibrary.org/works/merge?records=OL99529W,OL27228774W,OL28078149W,OL28101686W,OL28124222W,OL28139422W Set the primary work to something other than the first entry on the list to trigger the error condition.

Stakeholders

@mheiman @cdrini