As a wikidata editor,
I want to be able to add references when editing or creating a statement on mobile
So that the statement can be more precise

a/c

• When the 'add reference' button is clicked, the add reference form is opened
• This form is an overlay which blocks scrolling on the form below
• When the form is exited, the user is returned to the same place they were at before the form opened
• The edit reference form matches the figma design but is not pixel perfect
• Once the user arrives to the form, the initial input form - codex component Lookup - is already active, but the dropdown only opens once the user starts typing (as in desktop)
• Once the user selects or types in a valid entry, the second field appears and is already active, but once again the dropdown only opens when the user starts typing
• valid reference datatypes available would be 'simple text inputs'
• property suggestor should only make 'simple text inputs' available
• once both values are inserted correctly the add button on top becomes active, and if the user clicks it, he returns to the previous screen where he can now see his qualifiers
• the closing cross on the upper left corner takes the user back to the previous screen

Note: dev's choice for how to manage the multiple overlay. one option is main screen -> edit statement modal overlay -> reference modal overlay). Ideally it should be the same or nearly the same as in T402431

For later (aka a future task):

• both lookups can show up to 6 suggestions
• the lookups dropdown type is "initial suggestions" (component behaviour) and the menu items include a description (also component behaviour)