Allowing ConnectionManager and ConnectionPool to be disposed of both synchronously and asynchronously

[sburmanoctopus]

[sc-53245]

Background

When we tried using the latest Halibut in Octopus Server, tests would time out.

Results

Related to OctopusDeploy/Issues#8266

Before

Octopus Server would dispose of the Halibut runtime via Autofac, which would sense that the IHalibutRuntime implemented IAsyncDisposable.

But this completely ignores whether the feature toggle is turned on.

As a result, it would try to dispose a 'synchronous' Halibut 'asynchronously'.

This would cause the ConnectionManager to be disposed of asynchronously, which throws an exception if that occurs.

After

We have now made both ConnectionManager and ConnectionPool be disposable asynchronously.

This solves the issue, but also, it is probably a good idea to allow both paths of disposal to be allowed.

While here, we also noticed that CreateNewConnection is never called (so it was deleted).

We also had to reinstate OSSupportsWebSockets, as this is used in Octopus Server.

How to review this PR

Quality ✔️

Pre-requisites

• I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• I have considered informing or consulting the right people, according to the ownership map.
• I have considered appropriate testing for my change.

[shortcut-integration]

This pull request has been linked to Shortcut Story #53245: Make TentacleRemoteEndpointFacade and ScriptObserver support Sync and Async RPC calls.

[nathanwoctopusdeploy]

LGTM