* Add sample_text to Libre Barcode 39 Text METADATA
Libre Barcode 39 Text only supports a limited set of characters, "0123456789abdefghijklmnopqrstx". So having a pre-defined sample_text is more suitable for Libre Barcode 39 Text.
* Update to_sandbox.txt
ofl/shafarik # https://github.com/google/fonts/pull/8768
ofl/sixtyfourconvergence # https://github.com/google/fonts/pull/8908
ofl/triodion # https://github.com/google/fonts/pull/8768
+ofl/librebarcode39text # https://github.com/google/fonts/pull/9080
# Sample texts
lang/languages/agq_Latn.textproto # https://github.com/google/fonts/pull/9054