[examples][cli][routing-utils][static-build] replace deprecated String.prototype.substr() (#7588)

.substr() is deprecated so we replace it with .slice() or substring() which aren't deprecated
Signed-off-by: Tobias Speicher <rootcommander@gmail.com>

Co-authored-by: Steven <steven@ceriously.com>

test/lib/deployment/test-deployment.js

@@ -199,7 +199,7 @@ async function testDeployment(
       probe.path =
         probe.path.substring(0, nextScriptIndex) +
         scriptRelativePath +
-        probe.path.substr(scriptNameEnd + 1);
+        probe.path.slice(scriptNameEnd + 1);
     }
 
     const probeUrl = `https://${deploymentUrl}${probe.path}`;