fix(client): dispose credentials subscription on every close() path

[lazerg]

Description

Fixes #3390.

close() only disposed the streaming credentials subscription on the path where the command queue still had pending commands. On a graceful shutdown of an idle client the queue is already empty, so close() hit the early return resolve() and left the subscription alive. With @redis/entraid that keeps the token-refresh timer armed and the process never exits.

The dispose call now runs before the empty-queue early return, so both paths release the subscription, matching what destroy() already does.

The new test connects a client with a streaming credentials provider to a mock TCP server, closes it with an empty queue, and asserts the subscription was disposed.

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Checklist

• Does npm test pass with this change (including linting)?
• Is the new or changed code fully tested?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

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Note

Low Risk
Small lifecycle fix aligned with destroy()/quit(); behavior change only affects graceful close with streaming auth when the queue is empty.

Overview
close() now disposes the streaming credentialsSubscription at the start of shutdown, before the command-queue empty check. Previously that cleanup only ran on the branch that waited for pending replies, so an idle client could exit close() without calling dispose()—leaving token-refresh timers alive (e.g. with @redis/entraid) and preventing process exit.

A regression test connects with a streaming credentials provider, **close()**s with an empty queue, and asserts dispose ran. countRespCommands was hoisted to module scope for shared mock-server use.

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[nkaradzhov]

@lazerg thanks, this looks good to go!