Fix camera setup modal not closing and navigation not working

[Gold856]

Description

#1978 fixed the modal not working, but the modal could not be closed, and navigation to the Camera Matching tab didn't work either. This is because v-model attempted to write to the read-only needsCamerasConfigured computed property, and since it couldn't be set to false, the modal stayed up. This has been changed so that a separate ref is used to track the state of the modal, which is more consistent with how other modals are set up. Navigation to the Camera Matching tab has also been fixed by using <router-link>. Finally, the warningShown and needsCamerasConfigured properties have been deduplicated and moved to the camera settings store, motivated by the fact that there's a typo in the photon-sidebar version (PlaceHolder instead of Placeholder).

Meta

Merge checklist:

• Pull Request title is short, imperative summary of proposed changes
• The description documents the what and why
• If this PR changes behavior or adds a feature, user documentation is updated
• If this PR touches photon-serde, all messages have been regenerated and hashes have not changed unexpectedly
• If this PR touches configuration, this is backwards compatible with settings back to v2024.3.1
• If this PR touches pipeline settings or anything related to data exchange, the frontend typing is updated
• If this PR addresses a bug, a regression test for it is added

[samfreund]

It works!

[Gold856]

I should also note this fixed the Camera Matching tab text being completely static. It now pulsates in red when cameras need configuring.