* fix(@cal.com/web): update debounce logic to work correctly and not show non-premium usernames as premium - removes redundant useMemo hook from UsernameTextfield.tsx & PremiumTextField.tsx - cancles the debounceAPICall on every unmount of UsernameTextfield.tsx & PremiumTextfield.tsx via useEffect cleanup function Fixes #15628 * fix(@cal.com/web): update the debounce logic to use the pre-existing useDebounce hook - update the debounce logic in UsernameTextField.tsx & PremiumTextField.tsx to use the pre-existing useDebounce hook instead of loadsh debounce - update the debounce delay to 600ms to be consistent with the signup.tsx behavior Fixes #15628 * fix: signup debounce not working properly --------- Co-authored-by: Amit91848 <samit91848@gmail.com>