Issue with loading indicator appearance in Fast template

[TheoMathurin]

Panel 1.4.1

The loading spinner is not displayed as it is should in Fast template.

There is a mixup between the default (arc) and what's supplied to pn.config.loading_spinner. The spinner itself stays the default arc, with the supplied dots acting as a visibility mask. This issue will be best conveyed by showing the screencast.

Also, the supplied colour is not taken into account.

Taking the example from the docs:

import time
import panel as pn
import holoviews as hv
import numpy as np

pn.extension(loading_spinner='dots', loading_color='#00aa41', template='fast')
hv.extension('bokeh')

button = pn.widgets.Button(name="UPDATE", button_type="primary", sizing_mode='stretch_width')

def random_plot(event):
    if event: time.sleep(5)
    return hv.Points(np.random.rand(100, 2)).opts(
        responsive=True, height=400, size=8, color="green")

pn.Column(
    button,
    pn.param.ParamFunction(pn.bind(random_plot, button), loading_indicator=True)
).servable()