internal/pipewire: handle SecurityContext::Create error

This method can result in an error targeting it, so it is handled here. This change also causes a call to Create to also Core::Sync, as it should have done.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pipewire/pipewire_test.go

@@ -680,9 +680,6 @@ func TestContext(t *testing.T) {
 	}); err != nil {
 		t.Fatalf("SecurityContext.Create: error = %v", err)
 	}
-	if err := ctx.GetCore().Sync(); err != nil {
-		t.Fatalf("Sync: error = %v", err)
-	}
 
 	// none of these should change
 	if coreInfo := ctx.GetCore().Info; !reflect.DeepEqual(coreInfo, &wantCoreInfo0) {