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_v1/picture_classification.json

@@ -222,7 +222,7 @@
       "prov": [
         {
           "bbox": [
-            134.9200439453125,
+            134.9199981689453,
             281.78173828125,
             475.6635437011719,
             487.109375
@@ -244,7 +244,7 @@
       "prov": [
         {
           "bbox": [
-            218.8155517578125,
+            218.81556701660156,
             283.10589599609375,
             391.96246337890625,
             513.9846496582031