Hierarchical browse returns only first 20 results when searching/filtering

[ZahraaChreim-Atmire]

Describe the bug

When using hierarchical browse in DSpace (7.x and 10.x), if a search term matches more than 20 entries, only the first 20 are rendered. The UI does not support paginated loading, so additional results are inaccessible.

Example:
https://demo.dspace.org/server/#/server/api/submission/vocabularies/srsc/entries?filter=H&exact=false

To Reproduce

Steps to reproduce the behavior:

1. Create a custom vocabulary XML file containing more than 20 nodes (can be only 1 level deep).
   Example: nodes with label="label1" through label="label1000" and values like "value test 1" to "value test 1000".
2. Deploy the vocabulary in your backend instance.
3. Go to the hierarchical browse in the UI (/browse/srsc) and enter the query label.
4. Observe that only the first 20 matches are shown and no UI option exists to paginate or load the remaining results.

Expected behavior

All matching entries should be retrievable, either through automatic paging or via user-triggered pagination (e.g., “Show more” functionality).

Related work

Link to any related tickets or PRs here.