Guided Tours: Don't require sections due to bundle deps issue

[mcsf]

#7908's pathToSection change led to a lot of Calypso chunks unintentionally depending on chunks theme and themes. Fix this by requiring wordpress-com instead of sections while we think of a different approach, potentially using require.ensure.

h/t @blowery @ehg

To test

• Make sure the "blanket exit" feature introduced in GuidedTours: (blanket) exit by guessing user intent #7908 still works, as well as Guided Tours in general
• Make sure nothing funky happens during build and that theme and themes are not dependencies of other chunks
• Make sure all sections load correctly across Calypso

[matticbot]

Test live: https://calypso.live/?branch=fix/bad-sections-require

[lsinger]

I can confirm that this removes the theme and themes dependencies and that a) GuidedTours still works; b) GuidedTours blanket exit still works; and c) Calypso still works (I checked most sections). 👍