fix(onboarding): use default preset only if truthy (#16596)

Closes #16526

lib/workers/repository/onboarding/branch/config.ts

@@ -26,8 +26,9 @@ async function getOnboardingConfig(
   // Check for org/renovate-config
   try {
     const repo = `${orgName}/renovate-config`;
-    await getPreset({ repo });
+    if (await getPreset({ repo })) {
       orgPreset = `local>${repo}`;
+    }
   } catch (err) {
     if (
       err.message !== PRESET_DEP_NOT_FOUND &&
@@ -43,11 +44,14 @@ async function getOnboardingConfig(
     try {
       const repo = `${orgName}/.${platform}`;
       const presetName = 'renovate-config';
+      if (
         await getPreset({
           repo,
           presetName,
-      });
+        })
+      ) {
         orgPreset = `local>${repo}:${presetName}`;
+      }
     } catch (err) {
       if (
         err.message !== PRESET_DEP_NOT_FOUND &&
@@ -59,6 +63,9 @@ async function getOnboardingConfig(
   }
 
   if (orgPreset) {
+    logger.debug(
+      `Found org preset ${orgPreset} - using it in onboarding config`
+    );
     onboardingConfig = {
       $schema: 'https://docs.renovatebot.com/renovate-schema.json',
       extends: [orgPreset],