Description:
When inserting a new bibliography entry in the document, if the new entry is inserted between two existing entries, the index gets duplicated in both the reference and in the bibliography index

Steps to Reproduce:
1. Create a new LO Writer document
2. Insert some Lorem Ipsum paragraphs
3. Create a few new bibliography entries with the source being Document content and insert them into the document.
4. Create a Bibliography Index at the end. The index should be populated fine. Edit the index and change the entries to 'Number entries' instead of short name display.
5. Save the document as ODT, close and reopen.
6. Between any two existing bibliography references from the text, enther a new one. Let's say between [1] and [2], create and insert a new reference.
7. Observe that the new index is duplicated: now the indexes are [1], [2] and [2].
7. Update the bibliography index.
8. Notice that the bibliography index now contains duplicate entries: 1, 2, 2.

Actual Results:
The new bibliography index takes the same index as the next one, without renumbering them accordingly.

Expected Results:
A new index should be created and all the next indices should be renumbered: [1], [2], [3].
The Bibliography index should reflect this change and renumber the entries, without creating duplicates.


Reproducible: Always


User Profile Reset: No



Additional Info:
After saving and reopening the ODT document, sometimes the numbering is updated in the docuemnt, but the Bibliography index still shows duplicate numbers.