Remove android_manifest_for_lint from BUILD.gn files

The Chromium Roll into WebRTC isn't flowing
The first CL that caused the problem is https://webrtc-review.googlesource.com/c/src/+/175140/
The error is: ERROR at //examples/BUILD.gn:104:33: Assignment had no effect. android_manifest_for_lint = "androidapp/AndroidManifest.xml"
android_manifest_for_lint has ben removed so update BUILD files that use that feature to reflect this.

BUG=None

Change-Id: Ic3eb16eab8e4a4ab87daac9998d7a07373fec493
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/175569
Commit-Queue: Courtney Edwards <courtneyfe@google.com>
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31299}
diff --git a/examples/BUILD.gn b/examples/BUILD.gn
index 4d6d14d..26d67d6 100644
--- a/examples/BUILD.gn
+++ b/examples/BUILD.gn
@@ -101,7 +101,6 @@
 
   rtc_android_library("AppRTCMobile_javalib") {
     testonly = true
-    android_manifest_for_lint = "androidapp/AndroidManifest.xml"
 
     sources = [
       "androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java",
diff --git a/rtc_tools/network_tester/BUILD.gn b/rtc_tools/network_tester/BUILD.gn
index 47e600a..74b9403 100644
--- a/rtc_tools/network_tester/BUILD.gn
+++ b/rtc_tools/network_tester/BUILD.gn
@@ -115,7 +115,6 @@
 
   rtc_android_library("NetworkTesterMobile_javalib") {
     testonly = true
-    android_manifest_for_lint = "androidapp/AndroidManifest.xml"
 
     sources = [
       "androidapp/src/com/google/media/networktester/MainActivity.java",