Follow-up features and UI fixes for Panel Preview Page

Description

There are some UX and UI items we should fix before we remove the feature flag from the "Preview Panel MVC":

Blockers

Situation	Issue/MR	Status
Is it possible to have the "Define panel YAML below and preview panel. Learn more about panel types" text not as help text under the input but as separate description text above the input field?	!38381 (merged)	workflowproduction
Support mobile view for the two columns view, the two columns should stack on top of each other see !38381 (comment 389597746)	!38737 (merged)	workflowproduction
buttons will have to scale for mobile layout	!38737 (merged)	workflowproduction
documentation	!38977 (merged)	workflowproduction

Non-blockers

Situation	Issue/MR	Status
User can select a new time range, TBD: the time range could be separate or the same as in the dashboard	!38837 (merged)	workflowproduction
Refresh preview panel page	!39153 (merged)	workflowproduction
When cards are stacked, if possible, it'd be great to automatically scroll down to the preview once the user clicks "Preview panel".	#234100	Follow-up issue created
In the follow-up we should look into how buttons should scale on the smallest screen sizes. I think we should make the buttons fill the whole card width on mobile, similar to what we do on the pipelines page.	!38737 (merged)	workflowproduction
"undefined" can be seen in single stat charts	!39067 (merged)	workflowproduction

Original Discussion

The following discussion from !37688 (merged) should be addressed:

• @mrincon started a discussion: (+2 comments)

  @nadia_sotnikova Please help me review UX! As we add more functionality, more elements will be added, but I think we can check this iteration already.