token-cli: Fix updating metadata with offline signer

[joncinque]

Problem

Even though #5326 attempted to add offline signing support for update-metadata, it did not cover the case of updating metadata and transferring lamports to cover the new rent-exempt amount of the account.

Solution

Add a new --transfer-lamports parameter which is required for offline signing. With this PR, you can do:

$ spl-token update-metadata 5K8RVdjpY3CHujyKjQ7RkyiCJqTG8Kba9krNfpZnmvpS new-field new-value --sign-only --blockhash 5K8RVdjpY3CHujyKjQ7RkyiCJqTG8Kba9krNfpZnmvpS --transfer-lamports 10

Blockhash: 5K8RVdjpY3CHujyKjQ7RkyiCJqTG8Kba9krNfpZnmvpS
Signers (Pubkey=Signature):
 4SnSuUtJGKvk2GYpBwmEsWG53zTurVM8yXGsoiZQyMJn=3oMKkcJPxceeKByiqawu39LttYkpSUFBC3oLDsjkogBGvCiZ8SLpPFMaSt5pGWfT9fg6H8R8MXXzbRNX2Sx12RBa

[samkim-crypto]

Everything looks clean to me!