Build 26340.9233 does not add the new taskbar position setting. In that build, the taskbar section only mentions a fix for taskbar animations.
For current supported Windows 11 settings, the taskbar remains at the bottom of the screen, and Taskbar behaviors only lets taskbar icons be aligned center or left. There is no supported setting there to move the taskbar itself to the top or sides.
The new taskbar position option appears in Windows 11 Insider Beta Build 28020.2623, where it is available under:
Settings > Personalization > Taskbar > Taskbar behaviors
From there, Taskbar location on screen can be set to bottom, top, left, or right.
If the setting is missing on 26340.9233, that is expected for that build.
References: