Fixing GitHub Actions workflows Ubuntu 24 incompatibility (Lombiq Technologies: OCORE-219)

[Piedone]

Fix #17311.

• Configured the workflows to use Ubuntu 24 explicitly, so we prevent future surprise updates like this. In the future, Renovate will take care of this.
• Configured the Windows workflows to run an explicit version of Windows (the current 2022) too for the same reason.
• Factored out the actions/setup-dotnet call to an internal action, so it's easier to update. Also fixed the unit tests with that.
• Done test runs with Functional Tests - All Databases and Unit Tests - MacOS too.

Before merge the branch protection ruleset needs to be updated to require the ubuntu-24.04 and windows-2022 status checks.