Handle enabled: false via conditions_default

In this Android.bp file
```
my_cc_defaults {
  enabled: false,
  soong_config_variables: {
    my_bool_variable: {
       conditions_default: {enabled: false},
    }
  }
}
```
The inner enabled: false is a no-op because the top-level enabled is
false. Currently, bp2build will raise an exception for this Android.bp
file.

However, it does not need to. `productVariableConfigEnableLabels` runs
only if the top-level enabled is false. If it sees enabled: false via
conditions_default, it should just ignore it since it is a no-op.

Test: go test ./bp2build
Bug: 210546943
Change-Id: I816f209eaf21de65ddfbc2893e5255be94bcaa11
diff --git a/android/module.go b/android/module.go
index a662130..19502ba 100644
--- a/android/module.go
+++ b/android/module.go
@@ -1441,6 +1441,10 @@
 				axis := productConfigProp.ConfigurationAxis()
 				result.SetSelectValue(axis, bazel.ConditionsDefaultConfigKey, bazel.MakeLabelList([]bazel.Label{{Label: "@platforms//:incompatible"}}))
 				result.SetSelectValue(axis, productConfigProp.SelectKey(), bazel.LabelList{Includes: []bazel.Label{}})
+			} else if scp, isSoongConfigProperty := productConfigProp.(SoongConfigProperty); isSoongConfigProperty && scp.value == bazel.ConditionsDefaultConfigKey {
+				// productVariableConfigEnableAttribute runs only if `enabled: false` is set at the top-level outside soong_config_variables
+				// conditions_default { enabled: false} is a no-op in this case
+				continue
 			} else {
 				// TODO(b/210546943): handle negative case where `enabled: false`
 				ctx.ModuleErrorf("`enabled: false` is not currently supported for configuration variables. See b/210546943")
diff --git a/bp2build/soong_config_module_type_conversion_test.go b/bp2build/soong_config_module_type_conversion_test.go
index b91cf6d..8302ce8 100644
--- a/bp2build/soong_config_module_type_conversion_test.go
+++ b/bp2build/soong_config_module_type_conversion_test.go
@@ -1243,6 +1243,24 @@
     srcs: ["main.cc"],
     defaults: ["alphabet_sample_cc_defaults"],
     enabled: false,
+}
+
+alphabet_cc_defaults {
+    name: "alphabet_sample_cc_defaults_conditions_default",
+    soong_config_variables: {
+        special_build: {
+		conditions_default: {
+			enabled: false,
+		},
+	},
+    },
+}
+
+cc_binary {
+    name: "alphabet_binary_conditions_default",
+    srcs: ["main.cc"],
+    defaults: ["alphabet_sample_cc_defaults_conditions_default"],
+    enabled: false,
 }`
 
 	runSoongConfigModuleTypeTest(t, Bp2buildTestCase{
@@ -1259,7 +1277,13 @@
         "//build/bazel/product_config/config_settings:alphabet_module__special_build": [],
         "//conditions:default": ["@platforms//:incompatible"],
     }),
-)`}})
+)`,
+			MakeBazelTarget("cc_binary", "alphabet_binary_conditions_default", AttrNameToString{
+				"local_includes":         `["."]`,
+				"srcs":                   `["main.cc"]`,
+				"target_compatible_with": `["@platforms//:incompatible"]`,
+			}),
+		}})
 }
 
 func TestSoongConfigModuleType_ProductVariableIgnoredIfEnabledByDefault(t *testing.T) {