ion icons not displayed if they are hosted on a server requesting auth

I'm submitting a:

[x] bug report
[ ] feature request
[ ] support request

**ionicons version:**
```
ionicons v4.4.6
```

Current behavior:
Currently the icon class gets the svg content without sending the cookies in microsoft edge on desktop and in every navigator on iPad. By default, fetch won't send or receive any cookies from the server, resulting in unauthenticated requests if the site relies on maintaining a user session (to send cookies, the credentials init option must be set). This means that those svgs can't be hosted on a server requesting auth.

Expected behavior:
I would expect that a credentials init option is set to same-origin or include.

If there are cases I haven't thought of, please let me know. I'd also be happy with a config option to change the value.

Start by locating the icon class implementation that fetches SVG content and review how its fetch options are set. Reproduce the issue with icons hosted behind authentication in Edge or on an iPad, then verify that the request preserves the required session credentials and that existing unauthenticated icon loading still works.

Written by the indexing model from the issue text.