web-wallet: Use w3sper's minStake Amount Instead of Client-Side Environment Variable

[nortonandreev]

Description

Currently, the web app relies on a client-side environment variable to determine the minimum stake amount. However, we can now leverage w3sper's minStake value directly, ensuring consistency and reducing reliance on hardcoded values in the client.

Proposed Solution

• Replace the usage of the client-side environment variable with the minStake value provided by w3sper.
• Update any logic, validations, or UI elements that reference the minimum stake amount to use the w3sper value.
• Add error handling to manage cases where the minStake value is unavailable or returns an invalid value.

Additional Context

This change will help maintain alignment between the client and backend, improving the overall reliability of the staking process. Any dependencies on the environment variable should be identified and updated.