Change the color of the enhanced protection link in SSL interstitials.

The color of "turn on enhanced protection" should be consistent with the
color of "Learn more".

light mode
before: http://screen/8WidHUNBBQmzKgi
after: http://screen/3NR2qbG2f2P9zTq

dark mode
before: http://screen/BN2CLeG6XCyuqPU
after: http://screen/KraWTSsegRer2Zq

Bug: 1130721
Change-Id: I761731b565253cf800ef54999959ede0fc67c6ee
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2463592Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815770}

components/security_interstitials/core/browser/resources/interstitial_ssl.css

@@ -35,7 +35,3 @@
 .ssl-enhanced-protection-message .icon {
   background-image: url(images/light_bulb_grey.svg);
 }
-
-.ssl-enhanced-protection-message a:link {
-  color: blue;
-}