R1:f97c9d68d031

Fix PHP 8.1 Fatal error in Figlet: Use square brackets instead of curly braces

Summary:
Replace curly with square brackets when accessing an array value. See
https://www.php.net/manual/en/migration74.deprecated.php#migration74.deprecated.core.array-string-access-curly-brace
https://wiki.php.net/rfc/deprecate_curly_braces_array_access#wasn_t_the_curly_brace_syntax_deprecated_once_before

Closes T15406

Test Plan:
Fixed these two lines; afterwards Figlet rendered in task comment preview. Example figlet…