collab_ui: Show channel list while reconnecting (#37107)

This PR makes it so the channel list will still be shown while
reconnecting to Collab instead of showing the signed-out state.

In order to model the transitional states that occur while reconnecting,
we needed to introduce a new `Status::Reauthenticated` state that we go
through when signing in as part of a reconnect. This is because we
cannot tell from `Status::Authenticated` alone if we're authenticating
for the first time or reauthenticating.

Release Notes:

- N/A

crates/workspace/src/workspace.rs

@@ -6890,7 +6890,8 @@ async fn join_channel_internal(
             | Status::Authenticating
             | Status::Authenticated
             | Status::Reconnecting
-            | Status::Reauthenticating => continue,
+            | Status::Reauthenticating
+            | Status::Reauthenticated => continue,
             Status::Connected { .. } => break 'outer,
             Status::SignedOut | Status::AuthenticationError => {
                 return Err(ErrorCode::SignedOut.into());