fix(pypdfium): resolve overlapping text when merging bounding boxes (#1549)

get merged_text from boundingbox instead of merging it to prevent overlaps

Signed-off-by: Pedro Ribeiro <pedro_ribeiro_93@hotmail.com>

tests/data/groundtruth/docling_v2/picture_classification.json

@@ -334,7 +334,7 @@
         {
           "page_no": 1,
           "bbox": {
-            "l": 134.9200439453125,
+            "l": 134.9199981689453,
             "t": 487.109375,
             "r": 475.6635437011719,
             "b": 281.78173828125,
@@ -372,7 +372,7 @@
         {
           "page_no": 2,
           "bbox": {
-            "l": 218.8155517578125,
+            "l": 218.81556701660156,
             "t": 513.9846496582031,
             "r": 391.96246337890625,
             "b": 283.10589599609375,