Update background color of warning icon in submit dialog

Change-Id: I042b622d563ccafca91c54fcb413faad1d5e4826
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
index 99094d2..29b3752 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_html.ts
@@ -25,7 +25,7 @@
       margin-bottom: var(--spacing-l);
     }
     .warningBeforeSubmit {
-      color: var(--error-text-color);
+      color: var(--warning-foreground);
       vertical-align: top;
       margin-right: var(--spacing-s);
     }