Have ConvertWBp2build use Bp2buildMutatorContext

This no-op refactoring facilitates some upcoming functional changes for
"bp2build allowlist v2". The work requires that the bp2build conversion
mutator be changed from a TopDown mutator to a BottomUp mutator.
Refactoring all bp2build-related methods so that they use Bp2buildMutatorContext
makes it easier to make this functional change without touching tens of
files and multiple projects.

Bug: 285631638
Test: m bp2build
Change-Id: I3d1ef3064146e959c6f0dc315350fc9764bf2bd2
diff --git a/android/defaults.go b/android/defaults.go
index e0e6e5c..cc723f7 100644
--- a/android/defaults.go
+++ b/android/defaults.go
@@ -180,7 +180,7 @@
 
 // ConvertWithBp2build to fulfill Bazelable interface; however, at this time defaults module are
 // *NOT* converted with bp2build
-func (defaultable *DefaultsModuleBase) ConvertWithBp2build(ctx TopDownMutatorContext) {
+func (defaultable *DefaultsModuleBase) ConvertWithBp2build(ctx Bp2buildMutatorContext) {
 	// Defaults types are never convertible.
 	ctx.MarkBp2buildUnconvertible(bp2build_metrics_proto.UnconvertedReasonType_TYPE_UNSUPPORTED, "")
 }