fix: Update tests and examples for docling-core 2.5.1 (#449)

* Update tests for docling-core 2.5.0

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

* Add export with referenced images to export_figures example

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

* Fix OCR tests

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

* Revert "Fix OCR tests"

This reverts commit 12b575946f51950fcacece99d4d6eb682125d779.

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

* Update lockfile for docling-core 2.5.1

Signed-off-by: Christoph Auer <cau@zurich.ibm.com>

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Signed-off-by: Christoph Auer <cau@zurich.ibm.com>