Improve text selection accuracy by using the real font family

[ouchuan]

Enhanced the text layer creation process by using the real font family instead of the fallback font name. This change ensures that text selection is more accurate.

fixes: #19207

[ouchuan]

Since we need the original font to create a text layer, we need to preserve the font face here.
This may increase memory usage but can improve rendering speed when resizing, as we don’t need to load the font again.

[Snuffleupagus]

Sorry, but unfortunately this isn't a correct solution since it'll first of all not work correctly for non-embedded fonts.
Even for embedded fonts this will probably not work correctly in general, since there's no guarantee that the font actually contains all the glyphs needed in the textLayer (consider e.g. ligatures and other combined glyphs).
Also, given the glyph re-mapping that's done during the PDF.js font parsing this might to lead to incorrect copy-and-paste results.

Thanks for the patch, but unfortunately this is a much more complicated topic than it may seem at first glance (since I recall seeing a WIP patch by @calixteman some time back).

[ouchuan]

ok. thanks for your explanation