input: Show the start of a long value after set_value

[hlcfan]

Description

Ensure the cursor is at the start when setting text. This fixes the issue when an input value is long, it shows the latter part of the value after setting value.

How to Test

test_set_value_move_cursor_to_start

Checklist

• I have read the CONTRIBUTING document and followed the guidelines.
• Reviewed the changes in this PR and confirmed AI generated code (If any) is accurate.
• Passed cargo run for story tests related to the changes.
• Tested macOS, Windows and Linux platforms performance (if the change is platform-specific)

[madcodelife]

Thanks for the fix!
I tweaked it to keep the caret at the end (like an HTML input) while scrolling the view to the start.