This is a backport of Core [[https://github.com/bitcoin/bitcoin/pull/14383 | PR14383]] and [[https://github.com/bitcoin/bitcoin/pull/15023 | PR15023]]
PR 14383 description:
> There is a Debug window leftover in the system tray icon menu after [[https://github.com/bitcoin/bitcoin/pull/3392 | PR3392]] merging.
> This PR makes both the app menu and the systray icon menu consistent.
PR15023 description:
> [[https://github.com/bitcoin/bitcoin/pull/14383 | PR14383]] moved the debug window's menu position, to make it conditional on wallet mode. The rationale given was to match the behaviour of the 'Help' menu.
>
> [[https://github.com/bitcoin/bitcoin/pull/14573 | PR14573]] replaced the 'Help' menu's conditional debug window with an unconditional list of items in the new 'Window' menu.
>
> This PR reverts the no-longer-applicable part of #14383, putting the debug window back on the tray menu unconditionally, and in the position it previously had.
Note: PR14573 was backported in D7892