Allow partial match in profile metadata label

[shuuji3]

Elk can detect a certain profile metadata label such as mastodon or bluesky and change its icon. But currently, it only allows the exact string match (case-insensitive) so if we add some extra strings like (sub account), it fails to recognize the label and fallback to a simple text label.

It would be useful if Elk could match partial text so that users can add extra information in the label.