[ModuleInterface] Fix implementation-only imported type leak in indirect conformance

Don't print indirect conformances for protocols that are
implementation-only imported. Indirect conformances are synthesized when
the middle protocol is internal and not printed in the swiftinterface.
This logic didn't previously check for implementation-only imports,
likely because type-checking usually forbids it. Let's still protect
this use case as we are considering relaxing this type-checking
restriction in the future.

rdar://78718838

lib/Frontend/ModuleInterfaceSupport.cpp

@@ -562,7 +562,8 @@ public:
           return TypeWalker::Action::Continue;
 
         if (isPublicOrUsableFromInline(inherited) &&
-            conformanceDeclaredInModule(M, nominal, inherited)) {
+            conformanceDeclaredInModule(M, nominal, inherited) &&
+            !M->isImportedImplementationOnly(inherited->getParentModule())) {
           protocolsToPrint.push_back({inherited, protoAndAvailability.second});
           return TypeWalker::Action::SkipChildren;
         }