Background/Header image: Shrinked dropdown for date filtering

[pavelevap]

I noticed that for selecting Background image, "All dates" dropdown is shrinked. See attached screenshot. For selecting Header image it works well and it looks strange, but it is caused by other problem, that "Suggested image dimensions" is not diplayed even if presented in HTML:

<div class="instructions">Suggested image dimensions: 954 × 1300</div>

Instructions should be visible in this case, I guess...

[pavelevap]

Also titles for modal windows are different: "Select Image" (for Background) x "Choose Image" (for Header). It should be the same and consistent.

[celloexpressions]

Labels are reasonably easy to change, and I don't have a preference for which it is (should be changed on the image control). Backgrounds use the regular media modal, while headers use a special one, but that's likely a css fix regardless.

My general thought is that we shouldn't try to make headers and backgrounds the same until we make headers work like they should using the new stuff that all the other media controls use. Ie, headers need to be rewritten to extend the image control, like backgrounds, but with the additional cropping functionality. I'm not sure why it wasn't done that way in the first place, although the lack of functionality there probably drove headers to being more of a quick fix.

[ocean90]

30689.patch​ adds an option for [29813] and a state to the media frame for the upload control.

[ocean90]

In 30872:

Customizer: Remove date filter from the Header/Background Image upload frames.

Adds an option to wp.media.view.AttachmentsBrowser to hide the date filter added in [29813].

see #30689.

[johnbillion]

In 30915:

Customizer: Remove date filter from the Header/Background Image upload frames.

Adds an option to wp.media.view.AttachmentsBrowser to hide the date filter added in [29813].

Merges [30872] to the 4.1 branch.

See #30689.