Flip on Bazel mixed builds by default

This turns on Bazel-assisted builds for all Soong users.

If this CL breaks your build or your workflow, you may temporarily
disable Bazel mode by adding BUILD_BROKEN_DISABLE_BAZEL=1 to your
environment.

Test: TH
Test: Various off-band post-submit verification with "bazel staging
mode", which is an opt-in version of this feature.

Change-Id: Ifa44a79437ce76ea739ed661d4e2d567e0f4a4d5

ui/build/config.go

@@ -246,9 +246,7 @@ func defaultBazelProdMode(cfg *configImpl) bool {
 	if runtime.GOOS == "darwin" {
 		return false
 	}
-	// TODO(b/255364055): Flip this to true to enable bazel-mode by default
-	// for all users that don't opt out with BUILD_BROKEN_DISABLE_BAZEL.
-	return false
+	return true
 }
 
 func NewConfig(ctx Context, args ...string) Config {