Add validation to prevent consecutive invalid operators

[SavainB]

The function now includes additional logic to prevent users from entering consecutive invalid operators. This ensures that operators like +, -, *, and / are not entered one after another. The function checks the recent operators in the string and the parameter, returning the as is if two consecutive operators are detected. This commit enhances the functionality and improves the user experience by enforcing valid operator input.

Modified function: verification(displayText, new_caracter)

[netlify[bot]]

✅ Deploy Preview for calculator-dhanushnehru ready!

Name	Link
🔨 Latest commit	7c2f58480706dc9322b5d0579090ac9b10b6be4a
🔍 Latest deploy log	https://app.netlify.com/sites/calculator-dhanushnehru/deploys/647760e17b836500083b199f
😎 Deploy Preview	https://deploy-preview-98--calculator-dhanushnehru.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site settings.

[DhanushNehru]

Hey @SavainB on giving this it throws syntax error, please check that