Update the bridge URL in the sample code

[livid]

Update the bridge URL in the sample code from:

https://safe-walletconnect.gnosis.io/

To:

https://safe-walletconnect.safe.global/

According to the discussions here:

https://github.com/WalletConnect/WalletConnectSwift/issues/137

Without this update, the QR code generated by the sample code would only work with Trust Wallet but not with MetaMask or Rainbow because it seems only Trust handled a redirection in the bridge.