Obfuscated Text can pull characters from Unicode Private Use Areas

Obfuscated Text can pull characters from unicode blocks U+E000–U+F8FF, U+F0000–U+FFFFD, and U+100000–U+10FFFD, which are designated as Private Use Areas for user-defined custom characters. This can cause problems for resource packs using custom characters that have colors, large height and ascent that break out of typical font bounds, or other abnormal font features not intended to be used outside of specific cases.

Steps to Reproduce

1. Run the following command:

   /setblock ~ ~ ~ minecraft:oak_sign{front_text:{has_glowing_text:true,color:"white",messages:[{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"}]},back_text:{has_glowing_text:true,color:"white",messages:[{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"},{obfuscated:1b,text:"aaaaaaaaaaaaaaa"}]}}

2. Apply the attached Resource Pack

3. Notice the unintended characters appearing