[Android] Revert setting ExternalNavigationHandler DEBUG member to true

I inadvertently landed a change that set this member to true rather
than false :P. This landed in
https://chromium-review.googlesource.com/c/chromium/src/+/2132385.

Fortunately the above CL first landed in 84:
https://storage.googleapis.com/chromium-find-releases-static/955.html#955b7118ab87d23cbb053608efa451ae9bd80d20
Hence there doesn't need to be any question of whether this change would
be worth merging to 83 or not.

Bug: 1031465
Change-Id: I49e0c780f512c8786770851fa56cdcbc03d66608
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2144051Reviewed-by: Mugdha Lakhani <nator@chromium.org>
Commit-Queue: Colin Blundell <blundell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757805}

components/external_intents/android/java/src/org/chromium/components/external_intents/ExternalNavigationHandler.java

@@ -48,7 +48,7 @@ public class ExternalNavigationHandler {
     private static final String TAG = "UrlHandler";
 
     // Enables debug logging on a local build.
-    private static final boolean DEBUG = true;
+    private static final boolean DEBUG = false;
 
     private static final String WTAI_URL_PREFIX = "wtai://wp/";
     private static final String WTAI_MC_URL_PREFIX = "wtai://wp/mc;";