Users should be able to get a request link with 0 amount

[oskarleonard]

Expected behavior

• Since i can send a transaction with 0 and only a message, i should also be able to create a request link with that parameter.
• Make sure that leaving the amount field as untouched should not be possible.
• Update E2E test to correspond this behaviour. This scenario needs to be modified Request token should not generate a copy link if amount is 0

Actual behavior

Steps to reproduce

1. Open Request modal
2. Type 0 in amount

Which version(s) does this affect? (Environment, OS, etc...)