fix(linux): add reload privilege to mysql user

[bytestream]

$ sudo -u www-data -H php app-manager/artisan app:backup
[2024-11-19 13:33:21] Backing up database...
The dump process failed with a none successful exitcode.
Exitcode
========
2: Misuse of shell builtins

Output
======
<no output>

Error Output
============
mysqldump: Couldn't execute 'FLUSH TABLES': Access denied; you need (at least one of) the RELOAD or FLUSH_TABLES privilege(s) for this operation (1227)