fix: Livechat conversation not closing due to cross-tab interference

[aleksandernsilva]

Proposed changes (including videos or screenshots)

This PR mitigates a race condition happening on livechat and being reported intermittently on FLAKY-652.

The problem occurs when there's more than one tab running Livechat instance. When Livechat.closeChat is called, all tabs receive the system message livechat-close and initiate the closeChat() procedure. After the first tab finished, all other tabs are blocked due to the room being already closed. This sometimes blocks the tab where the close chat request was originated, which is not the desired behavior.

This PR mitigates this problem by:

1. Calling closeChat() only when the system message is received.
   This prevents the routine from being called twice. It unifies the logic, close chat requests initiated by either agent or visitor will follow the same routine. Finally, chat transcript request params are received via system message, the previous behavior could end up not displaying the transcript modal.
2. Removing the room existence check from closeChat()
   Initially the check was added was to prevent closeChat from being called twice (onFinishedChat and system message), change 1. takes care of this aspect. Since the function only executes client side mutations, it executing more than once in the same instance is problematic, but by different instances is acceptable.

This is a palliative solution, since at this moment no form of mutex seems to allow for the cross-tab communication needed. This behavior will be revisited in the future for a more robust solution.

Issue(s)

Steps to test or reproduce

To reliably reproduce this issue it is necessary to have more than one tab running livechat (in sync) and intentionally delay the call to processMessage (room.js) in one of the instances.

const processMessage = async (message) => {
	if (message.t === 'livechat-close') {
		const params = new URLSearchParams(window.location.search);

		if (params.has('delay')) {
			await new Promise((res) => setTimeout(() => closeChat(message).then(res), 5000));
		} else {
			await closeChat(message);
		}
	}
[...]

This issue can also happen during normal use, but very sporadically.

Further comments

No new tests were added since our current tests already cover this specific scenario.

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🦋 Changeset detected

Latest commit: 7d45a97

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@rocket.chat/livechat	Patch

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.44%. Comparing base (9f6a7b4) to head (7d45a97).
Report is 1 commits behind head on develop.

Additional details and impacted files

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