Remove default-text-color

Redundant, and replaced with primary-text-color.

Change-Id: I75ba49f6789b962ffd2c33e7cd1e04c4d6779326

polygerrit-ui/app/elements/change/gr-message/gr-message.html

diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.html b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
index fea01ca..8acf96f 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
@@ -119,7 +119,7 @@
         position: static;
       }
       .collapsed .author {
-        color: var(--default-text-color);
+        color: var(--primary-text-color);
         margin-right: .4em;
       }
       .expanded .author {