Fix toasts messages on Fullscreen mode

[Antreesy]

☑️ Resolves

• Follow up from Fix missing modals and popovers in Fullscreen mode #9309 (comment)
• Requires Add an ability to set and reset Toastify options globally nextcloud-libraries/nextcloud-dialogs#803
• Set the global selector for toast messages, to render toast messages inside #content-vue (which fixes Fullscreen Mode)
• Tested on Webclient

🚧 Tasks

• Code review
• Visual check

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not required
• 📘 API documentation in docs/ has been updated or is not required
• 📗 User documentation in https://github.com/nextcloud/documentation/tree/master/user_manual/talk has been updated or is not required
• 🔖 Capability is added or not needed

[ShGKme]

Mostly works, but one function is broken and JSDoc is not complete.

Alternative solution: to fix nextcloud-libraries/nextcloud-dialogs#380. Then we would only need to change the default container on fullscreen toggle.

[ShGKme]

I haven't tested yet, but it seems, it should be watch. Otherwise, it sets it once and doesn't update global selector with the getMainContainerSelector update.