fix: textinput multiline hidden lable issue on ios and web

[Balaji-Kotni]

Problem

When a TextInput gains focus (particularly with mode="flat"), the label disappears. This issue does not occur when multiline is set to false, where the label behaves as expected.

Motivation

A patchContainer was introduced to address an earlier issue (#2799). However, the container was assigned a zIndex of 2, which causes it to overlap and hide the actual label when the TextInput is focused.
To fix this, the zIndex has been reduced to 0. With this change, the label remains visible and functions correctly. The fix has been tested successfully on iOS, Android, and Web.

Related Issue

• Multiline TextInput label is not visible in flat mode #4756

Test Plan

All existing tests pass successfully.

[callstack-bot]

Hey @Balaji-Kotni, thank you for your pull request 🤗. The documentation from this branch can be viewed here.