Blocks availability: Make messages on unavailable blocks more actionable

[brbrr]

Steps to reproduce

1. Start with creating new post with Markdown and/or Form block
2. Disable these modules in wp-admin/admin.php?page=jetpack_modules
3. Open recently created post in Gutenberg editor
4. See block unavailability messages for these blocks

What I expected

To see more actionable items (links, buttons) on these blocks e.g.:

• To be able to have an "Activate" button to activate the missing module
• "Learn more" link to find out why I see this

What happened instead

I get not a really helpful message:
"Your site doesn’t include support for the "jetpack/contact-form" block. You can leave this block intact or remove it entirely."

Screenshot / Video

Primary issue

#32401

[gwwar]

Let's scope the issue down to our Jetpack blocks ;) If y'all agree do you mind updating the issue title?

[goldtreefrog]

I know this is an old thread, but as I encountered the exact same unhelpful message today, I want to second this request for a more helpful message when a block is unavailable.

(I was trying to copy a WordPress.com site to Local by Flywheel for testing before eventual migration. Feedback custom post types won't import, and I vaguely remember that last time I had this problem, I resolved it by installing JetPack and activating the forms block before importing. I have no idea how to activate the forms block now, and my "Verbatum" Google search led me to one result - this very page. Others may get here the same way.)

[jeherve]

Related: #10903