Fix with poppler-26.01.0 -- poppler-26.04.0.

From https://gitlab.com/KrIr17/inkscape/-/commits/poppler_26_04_1.4.3

Index: src/extension/internal/pdfinput/poppler-utils.h
--- src/extension/internal/pdfinput/poppler-utils.h.orig
+++ src/extension/internal/pdfinput/poppler-utils.h
@@ -83,6 +83,8 @@ typedef std::shared_ptr<std::map<FontPtr, FontData>> F
 FontList getPdfFonts(std::shared_ptr<PDFDoc> pdf_doc);
 std::string getNameWithoutSubsetTag(std::string name);
 std::string getDictString(Dict *dict, const char *key);
+std::string getString(const std::string &value);
+std::string getString(const std::unique_ptr<GooString> &value);
 std::string getString(const GooString *value);
 std::string validateString(std::string const &in);
 
