[Media Router WebUI] Fix remaining AX_COLOR_01 warnings.

chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css

Index: chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css
diff --git a/chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css b/chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css
index 9730fa99f823beeef33611cf7627a2c1797ac4af..b85d2bff5e5465c41cf8004c12a48937e5021c5c 100644
--- a/chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css
+++ b/chrome/browser/resources/media_router/elements/issue_banner/issue_banner.css
@@ -41,6 +41,14 @@
   width: 100%;
 }
 
+.non-blocking > #buttons > .button {
+  color: var(--paper-blue-300);
+}
+
+.non-blocking > #buttons > #default-button {
+  -webkit-margin-end: 24px;
+}
+
 .non-blocking > div > #title {
   color: rgba(255, 255, 255, 0.87);
 }