MediaPicker - ability to to filter files by extension/type?

[jameslavery]

We need to filter files available to the user to only include certain file types (e.g. PNG, jpeg).

The native implementations on iOS and Android have the facility - but unless I'm missing something, the MAUI MediaPicker doesn't have this.

This would be a good feature to add, I think - unless someone's got a (relatively easy) way to achieve this with the existing MediaPicker.