Display a variable's value on hover in the script editor menu

[AlirieGray]

As a user
When I hover over a variable in the side menu in the script editor,
Then I would like to see a popup appear to the left of that variable showing me the value held by that variable
If there are multiple values that can be selected for that variable,
Then I would like to see a dropdown where I can select which value I want to use wherever that variable appears in the script I am currently editing

[AlirieGray]

Depends on #12162

[AlirieGray]

We may want to only run the query for the value when the user hovers over the variable, or when the variable is loaded into view in the sidebar menu.