Saved HTML files do not get CSS resources inlined

[chmielcode]

ALL software version info

python 3.8.7
panel 0.10.3
bokeh 2.2.3

Description of expected behavior and the observed behavior

Saved HTML files do not get CSS resources inlined.

        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/alerts.css" type="text/css" />
        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/card.css" type="text/css" />
        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/dataframe.css" type="text/css" />
        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/json.css" type="text/css" />
        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/markdown.css" type="text/css" />
        <link rel="stylesheet" href="http://localhost:5006/static/extensions/panel/css/widgets.css" type="text/css" />

Since there is no server running, the page loads without styles and with additional delay.

Complete, minimal, self-contained example code that reproduces the issue

import panel as pn
from bokeh.resources import INLINE
pn.panel('# Test').save("test.html", resources=INLINE)