Launcher: Add Error Handling for LOGOS_UID

[thw26]

The following lines fail after initial install but succeed after the user logs in.

LOGOS_UID="\$(find "\${HERE}/data/wine64_bottle/drive_c/users/\${LOGOS_USER}/AppData/Local/Logos/Data/"* -maxdepth 0 -type d | awk -F'/' '{print \$NF}')"; export LOGOS_UID;
if [ -z "LOGOS_UID" ]; then LOGOS_UID="NoUser"; export LOGOS_UID; fi

https://github.com/ferion11/LogosLinuxInstaller/blob/master/Launcher-Template.sh#L47-L48

When the find command fails to find the UID, the error/warning confuses users. Error handling should be added so that this command does not report a problem on first install.

Note that line 48 is referenced by the backup and restore commands. If NoUser is found, the backup/restore commands will throw an error that the user must log in before using the commands:

backup

restore