Revert "Enable isolated splits in canary and dev"

This reverts commit c7a74ee0.

Reason for revert: manifest entries missing for DFMs, see crbug.com/1149022

Original change's description:
> Enable isolated splits in canary and dev
>
> All major crashes have been fixed and numbers look good. M88 branch was
> just cut, so should be safe to enable now.
>
> Bug: 1126301
> Change-Id: I351d565e68f14af2411c71fa80f34852bab5455a
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2529729
> Reviewed-by: Andrew Grieve <agrieve@chromium.org>
> Commit-Queue: Clark DuVall <cduvall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#827387}

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

Change-Id: I44601726754ab4c7d46f35f0d21be9482dd058b1
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1126301, 1149022
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538519Reviewed-by: Clark DuVall <cduvall@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827514}

chrome/android/modules/buildflags.gni

@@ -13,7 +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 == "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.