Jetpack Dependencies: Update wording to reflect new Jetpack settings

The current user-facing wording in the notification box needs to be updated to better match the current Jetpack settings screens.

For example, the wording refers to modules, when Jetpack no longer refers to/organizes its settings in that way.

As another example, the wording talks about activating the Custom Content Types module for portfolio projects and testimonials, when testimonials and portfolios are now broken down individually:


Screenshot from Jetpack > Settings > Writing

A full audit should be done and all the necessary wording tweaked.