pw_cli: Default change pw_protobuf default

Changes pw_protobuf_compiler_GENERATE_LEGACY_ENUM_SNAKE_CASE_NAMES
default to False.

This commit may cause downstream CQ failures and therefore not yet
be mergeable.

Bug: b/266298474
Change-Id: Id7a7546fdfc7450540e449c30c30b8231a5c3032
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/126806
Reviewed-by: Alexei Frolov <frolv@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>
Commit-Queue: Alexei Frolov <frolv@google.com>
diff --git a/pw_protobuf_compiler/toolchain.gni b/pw_protobuf_compiler/toolchain.gni
index 806a963..4256fd2 100644
--- a/pw_protobuf_compiler/toolchain.gni
+++ b/pw_protobuf_compiler/toolchain.gni
@@ -25,5 +25,5 @@
   # kConstantCase. Set this variable to temporarily enable legacy SNAKE_CASE
   # support while you migrate your codebase to kConstantCase.
   # b/266298474
-  pw_protobuf_compiler_GENERATE_LEGACY_ENUM_SNAKE_CASE_NAMES = true
+  pw_protobuf_compiler_GENERATE_LEGACY_ENUM_SNAKE_CASE_NAMES = false
 }