Revert "[WebLayer] Enable WebLayer in split on canary"

This reverts commit 7cfe51d0.

Reason for revert: Suspected as the reason for Canary build failures.

Original change's description:
> [WebLayer] Enable WebLayer in split on canary
> 
> This enables WebLayer in a split in WebView bundles in canary. I tested
> on L-Q and ran all instrumentation tests on P with this setup.
> 
> Bug: 1105096
> Change-Id: I517bce4109531108a4fb3af64a87aa1f5d2a91bb
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412705
> Reviewed-by: Scott Violet <sky@chromium.org>
> Commit-Queue: Clark DuVall <cduvall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#807252}

TBR=sky@chromium.org,cduvall@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1105096, 1129288
Change-Id: I040fa6a2cd4dcfbfd006a49b32ec952625557132
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2414258Reviewed-by: Benoit L <lizeb@chromium.org>
Commit-Queue: Benoit L <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807818}

weblayer/variables.gni

@@ -2,15 +2,12 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/config/android/channel.gni")
-
 declare_args() {
   # Include the //weblayer code in WebView implementation APKs.
   webview_includes_weblayer = true
 
   # Whether WebLayer will be included as a DFM.
-  weblayer_in_split =
-      android_channel == "default" || android_channel == "canary"
+  weblayer_in_split = false
 }
 
 weblayer_product_config_java_package = "org.chromium.weblayer_private"