Migrate legacy_acp asset failed.

[yanguoyu]

There are some problems with migrating legacy_acp.

1. Asset accounts will not show legacy_acp, so I guess we can remove the migrate dialog and the user can migrate it to a new ACP asset account on Customized Assets page. What do you think? @Keith-CY

2. Migrate legacy_acp failed on Customized Assets page.

migrate-failed.mov

3. If there is only one address for the hard wallet and exist an asset account cell, we should better disable migration to a new asset account.

exist-asset-account.mov

[yanguoyu]

nervosnetwork/neuron#3062
Neuron support migrates to other wallet ACP accounts, so even if the current one has an ACP account, users can choose to migrate to exist. So the third point will not change.