Fix bp2build-progress generating an empty converted_modules list, and
duplicate module names.

We were using the value receiver on AddConvertedModule before, which
didn't actually mutate the internal slice state.

Test: Run bp2build-progress.py
Change-Id: Ic60f8f6214a91dc129abf62c57dd0b85efffb283
diff --git a/bp2build/build_conversion.go b/bp2build/build_conversion.go
index f7b392b..07f492e 100644
--- a/bp2build/build_conversion.go
+++ b/bp2build/build_conversion.go
@@ -308,9 +308,8 @@
 					}
 				}
 				targets = generateBazelTargets(bpCtx, aModule)
+				metrics.AddConvertedModule(m.Name())
 				for _, t := range targets {
-					// only add targets that exist in Soong to compatibility layer
-					metrics.AddConvertedModule(m.Name())
 					metrics.RuleClassCount[t.ruleClass] += 1
 				}
 			} else {