fix: Correct CSV file path in update-lgsm command (#4917)

The distro CSV file was being fetched with an absolute path
instead of a repository-relative path, causing malformed URLs
like /master//home/user/lgsm/data/debian-12.csv

Changed fn_fetch_file_github first parameter from "${datadir}"
to "lgsm/data" to match the correct repository path structure.

Fixes #4856: ERROR: Downloading debian-12.csv on update-lgsm

Author: dgibbs64

lgsm/modules/command_update_linuxgsm.sh

@@ -188,7 +188,7 @@ if [ -f "${datadir}/${distroid}-${distroversioncsv}.csv" ]; then
 		fn_print_update_eol_nl
 		fn_script_log "Checking ${remotereponame} ${distroid}-${distroversioncsv}.csv"
 		rm -f "${datadir:?}/${distroid}-${distroversioncsv}.csv"
-		fn_fetch_file_github "${datadir}" "${distroid}-${distroversioncsv}.csv" "${datadir}" "nochmodx" "norun" "noforce" "nohash"
+		fn_fetch_file_github "lgsm/data" "${distroid}-${distroversioncsv}.csv" "${datadir}" "nochmodx" "norun" "noforce" "nohash"
 	else
 		fn_print_skip_eol_nl
 		fn_script_log_pass "Checking ${remotereponame} ${distroid}-${distroversioncsv}.csv"