Temporarily disable isolated splits to get canary coverage

We are planning on running binary experiments for isolated splits
enabled/disabled on M89. I want to make sure there are no problems with
the disabled version before branch cut. I'll revert this CL after a
couple days.

Bug: 1150162
Change-Id: I20061a079e897058625506dab810c4584c200fec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2618367
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#841596}

chrome/android/modules/buildflags.gni

@@ -13,8 +13,7 @@ declare_args() {
   # other DFMs.
   # TODO(crbug.com/1126301): The binary size tools need to be updated to include
   # DFM code before this can be enabled on stable.
-  enable_chrome_module = android_channel == "default" ||
-                         android_channel == "canary" || android_channel == "dev"
+  enable_chrome_module = false
 
   # Whether to enable DFMs which depend on the chrome DFM. These will be split
   # out of the chrome DFM using DexSplitter.