[TASK] Improve custom/ fixed amount input display & explanation

[monaiuu]

Description

Improve amount input in withdrawal so that users can easily understand the difference between selecting a fixed vs. custom amount.

We should also make custom amount more explicit on withdrawal based on user feedback.

At first glance, the choice of amount is not clear to me as a user. I think these options, a fixed amount and a custom amount, should be open and more understandable at once.

Reference: https://github.com/webb-tools/webb-dapp/issues/1174#issue-1701563407

[monaiuu]

Overview

• A switch component is added to allow users to easily toggle between fixed and custom withdrawal amounts. The default setting will be the fixed amount, and users can adjust the fixed amount using the adjustor component.
• (add tooltip to explain)
• user should not be able to select larger amount than available balance

Screenshot