fix(runner): improve config merging logic to prevent overwriting specific settings

[zboinek]

If not applied changes like Rate.XP.Kill.Vanilla are interpreted as Rate.XP.Kill so 4th lvl nested items doesnt work

In the official repository's runner/entrypoint.sh (https://github.com/Byloth/cmangos-docker/blob/master/runner/entrypoint.sh), the function is defined as:

1 function _replace_conf()
2 {
3 local SEARCH_FOR="${1}"
4 local REPLACE_WITH="${2}"
5 local FILENAME="${3}"
6
7 sed -i "/^${SEARCH_FOR}/c\${SEARCH_FOR} = ${REPLACE_WITH}" "${FILENAME}"
8 }

Why this is a bug in their repo:
The pattern /^${SEARCH_FOR}/ only checks if a line starts with the search term.

• If ${SEARCH_FOR} is Rate.XP.Kill, it matches Rate.XP.Kill.Vanilla.
• The c command then replaces that entire line.
• The result is that the expansion-specific settings are deleted and turned into duplicates of the global setting.