Revert "[infra] Add back generate_buildfiles.py to gclient hooks"

This reverts commit 9ed26558f137f77c8ff8c82217d86c3630ac304f.

Reason for revert: Failing builds due to missing gn runs

Original change's description:
> [infra] Add back generate_buildfiles.py to gclient hooks
> 
> Omitting this was a little fragile. We can add it back following the
> fix in https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1255446
> 
> Change-Id: Idfa0a08674bc1ea7ef19d7c9a96e17e6da293297
> Reviewed-on: https://dart-review.googlesource.com/c/84280
> Reviewed-by: Alexander Thomas <athom@google.com>
> Commit-Queue: Zach Anderson <zra@google.com>

TBR=whesse@google.com,sortie@google.com,zra@google.com,athom@google.com

Change-Id: I87cd9ddf5eca2e2a247a74eb1e666aa40bae7a48
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/84281
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Zach Anderson <zra@google.com>
diff --git a/DEPS b/DEPS
index ec830d0..4e7c835 100644
--- a/DEPS
+++ b/DEPS
@@ -490,8 +490,4 @@
     'pattern': '.',
     'action': ['python', 'sdk/build/vs_toolchain.py', 'update'],
   },
-  {
-    "pattern": ".",
-    "action": ["python", Var("dart_root") + "/tools/generate_buildfiles.py"],
-  },
 ]