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/sysprop/sysprop_library.go b/sysprop/sysprop_library.go
index a2c0fb7..d16bf32 100644
--- a/sysprop/sysprop_library.go
+++ b/sysprop/sysprop_library.go
@@ -591,7 +591,7 @@
 }
 
 // TODO(b/240463568): Additional properties will be added for API validation
-func (m *syspropLibrary) ConvertWithBp2build(ctx android.TopDownMutatorContext) {
+func (m *syspropLibrary) ConvertWithBp2build(ctx android.Bp2buildMutatorContext) {
 	labels := cc.SyspropLibraryLabels{
 		SyspropLibraryLabel: m.BaseModuleName(),
 		SharedLibraryLabel:  m.CcImplementationModuleName(),