fix: Crash cake staking input (#10623)

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## PR-Codex overview
This PR updates the `LockCakeForm.tsx` file in the CakeStaking component
to handle input of a decimal point more effectively.

### Detailed summary
- Modified the `onUserInput` function to handle input of a decimal point
by converting it to '0.' before passing it to the function.

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Co-authored-by: Chef Jerry <144641937+ChefJerry@users.noreply.github.com>

apps/web/src/views/CakeStaking/components/LockCakeForm.tsx

@@ -32,7 +32,7 @@ const CakeInput: React.FC<{
   const onInput = useCallback(
     (input: string) => {
       setPercent(null)
-      onUserInput(input)
+      onUserInput(input === '.' ? '0.' : input)
     },
     [onUserInput],
   )