Client signatures expects Pubkey|Keypair for signer accounts

[julianzamt]

Describe the bug
The generated program client "sendAndConfirm" signatures expect a Union Type defined as (Publickey | Keypair) for params that later are used to sign the tx. Therefore, a TS error is not raised when passing a Pubkey as arg, but the tx will fail with "signature verification failed", since the private key was not provided.

To Reproduce

- name: add_lamports_direct_mode
    solana:
      signers:
        - name: fee_payer
        - name: sender
    inputs:
      - name: sender
        type: sol:account_info
        solana:
          attributes: [ mut ]

Expected behavior
To produce a signature with type PublicKey when the signature is not required, and Keypair when it does.

Platform version:

• CLI Version [e.g. v0.1.0]
• GenService Version v0.8

Extension (mark with an X the extension):

• Solana Native [ ]
• Solana Anchor [x]