[BUG] Valkey 8.1 does not accept null bytes in script source code

[gmbnomis]

Describe the bug

Since commit b58088e "Adds support for running EVAL with different scripting engines (#1497)" Valkey
does not support null bytes in scripts anymore. (To be clear: this is not about handling strings with null bytes in scripts. It is about a script's source code containing null bytes)

To reproduce

In valkey-cli:

127.0.0.1:6379> eval "return '\\0';" 0
"\x00"
127.0.0.1:6379> eval "return '\x00';" 0
(error) ERR Error compiling script (new function): user_script:1: unfinished string near '<eof>'

Expected behavior

Prior to this change, a lua embedded zero and a real null byte both work:

127.0.0.1:6379> eval "return '\\0';" 0
"\x00"
127.0.0.1:6379> eval "return '\x00';" 0
"\x00"

Additional information

It is unclear to me whether this is an intentional change (that was not described in the release nodes)

(For us, it is not a required use case, but it broke one of our tests. We intended to use a lua zero in a string literal and because of the library we use, this ended up becoming a null byte)

[hpatro]

Tagging @rjd15372 to check if anything changed with the refactoring.

[madolson]

I was thinking it might be related to the fact the "code" object is a c string, which doesn't handle binary data. I suggested a patch because it would be a module breaking change, so we should prioritize it for the upcoming patch release if possible.