Caused by 3a1cf838.

Smooth view transitions only work when an operator is **invoked** (wont
work from **exec**, see `WM_operator_smooth_viewtx_get`).

Now 3a1cf838 changed the `operator_context` for some other operators
in the menu to 'EXEC_REGION_WIN' (for good reason). But setting
`operator_context` on a `uiLayout` will set context on the **root**
layout (not the actual sublayout alone), so all following operators
"inherited" the [changed] context.

Now make sure following operators get properly invoked again by giving
the right context.

Pull Request: https://projects.blender.org/blender/blender/pulls/107296