DevTools: [Audits] Hide "open in viewer" report feature.

Bug: 1000409
Change-Id: I2917f7d8a63b14fc8f13e692ed12551f437e9c9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1783245Reviewed-by: Paul Irish <paulirish@chromium.org>
Commit-Queue: Connor Clark <cjamcl@google.com>
Cr-Commit-Position: refs/heads/master@{#692854}

third_party/blink/renderer/devtools/front_end/audits/auditsPanel.css

@@ -28,6 +28,6 @@ button.view-trace {
 
 /** `window.opener` is null for windows opened from DevTools. This breaks
     the LH viewer app, so disable this feature. */
-.lh-export--viewer {
+.lh-tools--viewer {
   display: none !important;
 }