TinyMCE Editor toolbar icons not visible in high contrast mode

[sthorve]

Documentation/Product Version
TinyMCE 6 Documentation

Links to Page(s) affected
https://www.tiny.cloud/docs/tinymce/6/
Microsoft's Tool using this editor causing a accessibility issue

Description of Issue
When high contrast mode is turned on, the icons in the TinyMCE toolbar are not visible. This makes it difficult for users with low vision to use TinyMCE.

Steps to reproduce the issue

1.Open a web page with TinyMCE https://www.tiny.cloud/docs/tinymce/6/
2.Turn on high contrast mode.
3.Observe the TinyMCE toolbar.

Expected behavior
The icons in the TinyMCE toolbar should be visible.

Actual behavior
The icons in the TinyMCE toolbar are not visible.