Update cli.py to remove double negative typo

Ran into this error in the CLI stating the wallet did not not exist.  Looked into if this is an intentional double negative.  My research points to "no" it's a typo.

Looking at the logic:
1. utils.is_valid_wallet(wallet) returns a tuple where the first element (valid[0]) indicates if the wallet exists
2. The condition if not valid[0]: triggers when the wallet does NOT exist
3. So the error message should indicate the wallet doesn't exist

Author: calebcgates

bittensor_cli/cli.py

@@ -1726,7 +1726,7 @@ def wallet_ask(
             valid = utils.is_valid_wallet(wallet)
             if not valid[0]:
                 utils.err_console.print(
-                    f"[red]Error: Wallet does not not exist. \n"
+                    f"[red]Error: Wallet does not exist. \n"
                     f"Please verify your wallet information: {wallet}[/red]"
                 )
                 raise typer.Exit()