[Lotus Fountain Faucet] Enhance Error Messaging & Rate Limit Transparency

[barbaraperic]

Description

The "Too many requests: Wallet limit" error lacks clarity. Consider adding:

• Rate limit details (e.g., "You can request tFIL every X hours").
• A countdown or timestamp indicating when the user can request again.

Proposed version

Reference: FF UXIT Lotus Fountain Faucet Report

[rjan90]

Closed by #13104