sudoers parsing not honoring line continuation characters

Bug report

What operating system and version are you using?

version = 12.0.1
build = 21A559
platform = darwin

What version of osquery are you using?

version = 5.0.1

What steps did you take to reproduce the issue?

Created a sudoers file with line continuation characters:

User_Alias OTHER_USERS=foo,\
bar,\
baz
User_Alias NUM_USERS=#501,#502
User_Alias ALL_USERS = NUM_USERS,\
OTHER_USERS
Cmnd_Alias CMDS_1=/usr/bin/cmd1 "a\,b", \
    /usr/bin/cmd2
ALL_USERS ALL=(ALL)CMDS_1

(this as /etc/sudoers.d/eviltest is enough to validate the problem)

What did you expect to see?

The line continuation characters should be swallowed by the parsing and the rule details for the subsequent lines appear in the rule_details under the appropriate header.

What did you see instead?

The next lines appeared in the header field and the rule_details field was empty, indicating line continuation was not being done.

Reproduce the issue with the supplied sudoers content in /etc/sudoers.d/eviltest on macOS 12.0.1 using osquery 5.0.1. Inspect the parsed output, especially the header and rule_details fields, and trace the sudoers parser from that result. Done means continuation characters are swallowed and subsequent lines populate rule_details under the appropriate header.