Files Sidebar integration fails at switching conversations

[Antreesy]

When trying to start call sometimes (but it is often). try to close a call and start another call for another file?

• Instance exist from the first call and not cleaned up;
• Triggers this to open new tab: (and prevent navigation):
  

  spreed/src/router/router.ts

  Lines 116 to 120 in bedc1f5

  	if (to.name === 'conversation' && (from.params.token && from.params.token !== to.params.token)) {
  	// in case of a link to a different conversation, open it in a new tab
  	window.open(window.location.origin + router.resolve(to).href, '_blank', 'noopener,noreferrer')
  	// cancel the navigation in current tab
  	return false

• old conversation chat is opened from first call;
  -- conversation isn't joined -> joinCall fails

Originally posted by @Antreesy in #17860 (comment)

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On switching tabs / Talk integration still mounted, prev.conversation state is still valid -> should be destroyed instead