Import recovery phrase user-flow simplified for MVP-0

[xAlisher]

✅ Simplifications (agreed with @felicio)

Based on the user story:
🔗 [As a user, I want to import an Ethereum address into my wallet](https://www.notion.so/As-as-a-user-I-want-to-import-Ethereum-address-in-my-wallet-1ce8f96fb65c80bebd4ef78f9a944007?pvs=4)

Changes:

1. Single input field for the full recovery phrase, instead of individual fields per word
2. Unified error message for both invalid word count and incorrect spelling

Reason:

The original design was too complex to fit into the MVP-0 scope. This version reduces UI overhead while preserving core functionality.

Design:

https://www.figma.com/design/8IuYR751lsXg1F8bu8Cj8B/Wallet-Extension----Web?node-id=5609-60287&t=bYRb5vx1TGdgj2zq-1

@felicio please review

[felicio]

Reviewed, left just one comment https://www.figma.com/design/8IuYR751lsXg1F8bu8Cj8B?node-id=5729-37244&m=dev#1272415410.