[AW][Dev-UI] remove SafeBrowsingCommittedInterstitials flag

No change to logic. This removes the SafeBrowsingCommittedInterstitials
switch, which was removed in https://crrev.com/c/2138506.

Test: None
Change-Id: I464ee374f3656b49d0f973e23b7f2d858cbc34f8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2223368
Auto-Submit: Nate Fischer <ntfschr@chromium.org>
Commit-Queue: Carlos IL <carlosil@chromium.org>
Reviewed-by: Carlos IL <carlosil@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773925}

android_webview/java/src/org/chromium/android_webview/common/ProductionSupportedFlagList.java

@@ -66,8 +66,6 @@ public final class ProductionSupportedFlagList {
                             + "security checks."),
             Flag.baseFeature(
                     "WebViewBrotliSupport", "Enables brotli compression support in WebView."),
-            Flag.baseFeature("SafeBrowsingCommittedInterstitials",
-                    "Commits Safe Browsing warning pages like page navigations."),
             Flag.baseFeature(
                     "AppCache", "Controls AppCache to facilitate testing against future removal."),
     };