nits on avalanche key transfer command - merge to main

[meaghanfitzgerald]

Previously #2225

Why this should be merged

When prompted for the sender address, the user currently sees this improper prompt:

? Which key source should be used to  for the sender address?:
  ▸ Use stored key
    Use ledger

How this works

Changes the phrasing and corrects spacing so that the user sees:

? Which key should be used as the sender address?:
  ▸ Use stored key
    Use ledger

How this was tested

avalanche key transfer

How is this documented

~I am currently writing a doc on how to use this command: https://github.com/ava-labs/avalanche-docs/pull/1910`
I wrote a doc on how to use this command: https://docs.avax.network/tooling/transactions/native-send