Safari shows iCloud Keychain icon when `Pinput` uses `obscureText` on Flutter Web

[ppamorim]

Describe the bug

On Flutter Web in Safari, focusing a Pinput with obscureText: true shows the iCloud Keychain/password icon over the PIN boxes. The icon overlaps the input UI, usually near the last PIN cell.

---

To Reproduce

1. Run a Flutter Web app in Safari.
2. Render a Pinput with the following config:

    Pinput(
      length: 6,
      obscureText: true
      keyboardType: TextInputType.number,
      autofillHints: null,
      enableSuggestions: false,
    )