Track client-initiated shutdown for any pipe type

[bgrainger]

Fixes #2652

Previously, RecordQuit only recorded a client-initiated QUIT if _ioPipe was a SocketConnection, which is not true when using SSL.

Since there is a 1-1 relationship between PhysicalConnection and _ioPipe, store whether the client initiated the shutdown on the PhysicalConnection object instead of (only) delegating it to SocketConnection.

The line var pipe = connectingPipe ?? _ioPipe seems irrelevant to this PR because connectingPipe is only set once, in ConnectedAsync, and would be relevant only if an exception were thrown between when pipe is set and when its value is assigned to _ioPipe (i.e., between lines 1612-15).

[bgrainger]

(I'm not set on using Thread.VolatileRead/Write to store this information; it just seemed in line with what was already being done in SocketConnection.)

[bgrainger]

The branch name is wrong; this actually fixes #2652.

[bgrainger]

The PR CI job succeeded the first time: https://github.com/StackExchange/StackExchange.Redis/actions/runs/11786652807
This probably just needs to be re-run.

[NickCraver]

Thank you sir!

[teemka]

@bgrainger will you try reruning CI and merging? Thanks :)