Your question is not stated clearly.
If you are only wanting to replace the first occurrence of curly braces in your specific data with the second element in that group, you could use a negative lookahead to match the following comma.
$text = preg_replace('/{{[^|]*\|([^|]++)\|[^{}]++}}(?!,)/', '$1', $text);
Outputs..
Buster Bros, also called Pang and {{Nihongo|Pomping World|ãƒãƒ³ãƒ”ング・ワールド|Ponpingu WÄrudo|lead=yes}}, is a cooperative two-player arcade video game released in 1989 by Capcom
If you want to replace every occurrence of curly braces with the second element in that group.
$text = preg_replace('/{{[^|]*\|([^|]++)\|[^{}]++}}/', '$1', $text);
Outputs..
Buster Bros, also called Pang and Pomping World, is a cooperative two-player arcade video game released in 1989 by Capcom