[WebLayer] Build client AAR in gn_all

Bug: 1021126
Change-Id: I5c7e6a1fe0bd0f3f3fe96d9ef71cae242973d073
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898086Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712208}

BUILD.gn

@@ -342,6 +342,7 @@ group("gn_all") {
       "//tools/android/errorprone_plugin:errorprone_plugin_java",
       "//tools/android/kerberos/SpnegoAuthenticator:spnego_authenticator_apk",
       "//ui/android:ui_junit_tests",
+      "//weblayer/public/java:client_aar",
       "//weblayer/shell/android:weblayer_shell_apk",
     ]
     deps -= [