Upgrade to Mirador plugin v4.0.0 for IIIF

[tdonohue]

Description

Currently, we are using Mirador version 3.4.0 in our codebase, which was released in 2024.

Last October, Mirador version 4.0.0 was released which provided a "major refresh of many of the upstream dependencies". Many of these older dependencies of 3.x are now beginning to show their age already. So, we should consider an upgrade as soon as we are able.

Per the 4.0.0 release notes:

This release includes breaking changes and significant architectural refactoring. Upgrading from Mirador 3.x or earlier requires updates to custom plugins, integrations, or theming.

I have not attempted this upgrade, but it seems like it will require some additional testing to verify that Mirador behavior is not changed when IIIF is enabled.

Ideally, we should consider backporting any upgrades to Mirador, unless the upgrade requires significant code refactoring or similar.