Bump DeviceRunners from preview.1 to preview.5

[jamescrosswell]

Also dropped the net8.0 targets for device tests, since preview.5 does not support net8.0 (and this is EOL now).

Was originally meant to fix #4337:

• Exit code 78: PACKAGE_INSTALLATION_FAILURE when running iOS device tests #4337

That was resolved separately by pinning the version of xharness:

• ci: pin xharness #4339

@Flash0ver we could still go ahead and bump the DeviceRunners version as there are a number of other fixes/improvements here. We'll need to do this eventually when we want to support .NET 10 anyway.

#skip-changelog

[jamescrosswell]

Odd that this didn't work. On my local machine, bumping the device runner version resolved the issue.

I'm using Xcode 16.4 and Microsoft.DotNet.XHarness.CLI 10.0.0-prerelease.25360.1 locally (same as on CI), so I'm not sure what else to check. As I'm running out of ideas, I kicked off this thread in the Dotnet Evolution channel.

An alternative possible workaround would be to download the iOS 18.0 simulators and force the device tests to use these... eventually we'll have to solve this problem of course, but for the time being that could get our CI back up and running (and would have the added benefit of making CI more deterministic... so we choose when to bump simulator versions rather than having the environment bump this arbitrarily when MS or Apple release stuff).

[Flash0ver]

Superseded by #4339.
Fixed by pinning the version of Microsoft.DotNet.XHarness.CLI the the previous version of the preview NuGet feed of https://github.com/dotnet/xharness.

I believe this draft PR could be closed, but we still require a follow-up to fix a test that is failing on the device:
See #4339 (comment).

Or - we could still go forward with this PR as well, since the update of dependencies and removal of the out-of-support TFM does sound good regardless.

Actually ... I'll merge main into this PR, including #4339, and let's see what happens ... 🤞