Window from the scratchpad isn't shown on activation

## I'm submitting a…

[x] Bug ?

[x] Feature Request ?

[ ] Documentation Request

[ ] Other (Please describe in detail)

## Current Behavior
When a window that exists is in the scratchpad (in my case - Telegram) gets activated (by clicking on a tray icon, or a notification) - nothing happens.

## Expected Behavior
I'd expect the window to be shown in such case. It seems that the issue #2455 was about something similar and it got resolved. Also, the `focus_on_window_activation focus` option works correctly with Telegram, i.e. when I click on the tray icon or a notification - i3 jumps to the workspace with Telegram on it. That's why I think this might be a bug.

## Reproduction Instructions
1. Put the Telegram window (or any other that behaves the same on activation, I'm not really sure how activation works in different programs) in the scratchpad.
2. Click on the tray icon (or a notification).

## Environment
Output of `i3 --moreversion 2>&-`:

Binary i3 version:  4.19.2 (2021-02-27) © 2009 Michael Stapelberg and contributors

Running i3 version: 4.19.2 (2021-02-27) (pid 12345)

Loaded i3 config: /home/username/.config/i3/config (Last modified: 1144 seconds ago)


The i3 binary you just called: /usr/bin/i3

The i3 binary you are running: i3

## Config file
The only relevant line there is `focus_on_window_activation`, I think, but here you go:
https://github.com/AdamantGarth/dotfiles/blob/master/i3/config#L17

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- Linux Distribution & Version: Arch Linux
- Are you using a compositor (e.g., xcompmgr or compton): Yes, latest picom from Arch repos (`vgit-dac85`).