LibPDF/CFF: Read font dicts pointed to by the fdarray offset

The fdselect array (that we already read) maps eachs glyph ID
to an fdarray index. The font dict at that index then stores
information for that glyph.

In practice, this is used to assign different defaultWidthX /
nominalWidthX values to blocks of glyphs in CID-keyed fonts.

We don't do anything yet with the data, and we also don't send
data of CID-keyed CFFs into this parser either, so no behavior
change.

Userland/Libraries/LibPDF/Fonts/CFF.h

@@ -127,6 +127,7 @@ public:
         float defaultWidthX = 0;
         float nominalWidthX = 0;
         int fdselect_offset = 0;
+        int fdarray_offset = 0;
     };
     static PDFErrorOr<Vector<TopDict>> parse_top_dicts(Reader&, ReadonlyBytes const& cff_bytes);