Specify code output panel(s) in web component

[sra405]

We need to provide a clean output view when using the editor in block-to-text. The current (only) activity produces visual output only so the current thinking is:

• We provide a list of output pane strings to the web component
• We default to all available panes (and conditionally show visual still)
• If that array has length one we don't show the output pane tabs along the top

merge into https://github.com/RaspberryPiFoundation/editor-ui/tree/output-only-wc

[create-issue-branch]

Branch issues/906-Specify_code_output_panel_s_in_web_component created!