Set `'filter' => 'content'` on starter content "business info" widget

[dlh]

The text_business_info starter content widget currently prompts the user to move the content into the Custom HTML widget. To my eyes, neither the legacy text widget nor the HTML widget provide as good an editing experience for that widget's content as a TinyMCE-enabled text widget (see screenshots). So, the attached patch would set 'filter' => 'content' on the widget to ensure it uses TinyMCE.

[dlh]

41410.2.diff​ is a version with 'visual' => true, as proposed in #41394.

[westonruter]

@dlh Wow, excellent find! I wonder if fundamentally instead of setting visual to true if we should instead change the text to cause it to such that legacy mode would not have been triggered to begin with? In 41410.3.diff​ you can see what I mean. Strictly 'visual' => true (or 'filter' => 'content') is even not necessary here because the text would not match is_legacy_instance anyway.

[dlh]

Replying to westonruter:

@dlh I wonder if fundamentally instead of setting visual to true if we should instead change the text to cause it to such that legacy mode would not have been triggered to begin with?

That works, too. I'm not sure I have a preference. It does seem like the text of 41410.3.diff​ is closer to what gets saved in the text widget if you try to manually recreate the content of the starter widget, which might be another reason to make the change.

[westonruter]

Depends on #41394.

[westonruter]

In 41136:

Customize: Update Text widget starter content to utilize visual mode.

Amends [38991].
Props dlh, westonruter.
See #35243, #38114.
Fixes #41410.

[westonruter]

Re-opening for 4.8.1

[westonruter]

In 41137:

Customize: Update Text widget starter content to utilize visual mode.

Merges [41136] onto 4.8 branch.
Amends [38991].
Props dlh, westonruter.
See #35243, #38114.
Fixes #41410 for 4.8.1.