ci: use Cirrus Runners for iOS Integration Tests

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Description

GitHub-hosted Runners keep pulling the rug under our feet, removing Xcode versions older than the latest 3 versions.
This semi-regularly, but continuously, breaks our CI.
We are in dire need of a stable Environment.

Cirrus Labs Runners to the rescue.
See also: getsentry/sentry-react-native#5485

Tasks

• switch .NET MAUI 9.0 Integration Tests for iOS to Cirrus Labs Runners
• switch .NET MAUI 10.0 Integration Tests for iOS to Cirrus Labs Runners

See

• chore: Device/integration tests for mobile on .net10 #4750 (comment)
• chore: Device/integration tests for mobile on .net10 #4750 (comment)
• chore: Device/integration tests for mobile on .net10 #4750 (comment)
• chore: Device/integration tests for mobile on .net10 #4750 (comment)
• chore: Device/integration tests for mobile on .net10 #4750 (comment)

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NET-576

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OpenAI seem to have acqui-hired Cirrus Labs: https://macstadium.com/blog/cirrus-labs-is-joining-openai