Error when using external_stylesheets or external_scripts with URL that has double-slash notation

[daattali]

The double slash notation can be used to fetch a resource using the same protocol that the current page is using. For example

dash::Dash$new(external_stylesheets = "//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css")
dash::Dash$new(external_scripts = "//cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js")

These should get the respective css/js file either from http:// or https:// depending on the current page. But instead an error is given:

Error: A valid URL must be included with every entry in external_stylesheets. Please sure no 'href' entries are missing or malformed.