[Bug]: Watermark for textboxes not visible properly across the app

### Describe the bug

The watermark (placeholder text) inside textboxes is not clearly visible in most places within the application. This makes it difficult for users to identify the expected input.

### Expected behavior

The watermark/placeholder text should be clearly visible and readable in all textboxes across the app.

### Screenshots/Recordings

### Steps to reproduce

Open the application.
Navigate to any screen with input textboxes ( wallet custom import, send).
Observe the watermark/placeholder text inside the textbox.

### Error messages or log output

```shell

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### Detection stage

During release testing

### Version

7.56.0

### Build type

None

### Device

iphone 15

### Operating system

iOS

### Additional context

_No response_

### Severity

_No response_

Start by reproducing the placeholder visibility issue on an iPhone 15 running iOS, focusing on the wallet custom import and send screens named in the report. Trace how textbox watermark styling is shared across those screens and the rest of the app. Done means placeholder text is clearly readable in all affected textboxes and the reported flows are verified.

Written by the indexing model from the issue text.