fix (ios-view): resolves race condition when setting preferredContentSize on view controller

[AdamAtri]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
• You have signed the CLA.
• All existing tests are passing: https://github.com/NativeScript/NativeScript/blob/master/tools/notes/DevelopmentWorkflow.md#running-unit-tests-application.
• Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/tools/notes/WritingUnitTests.md.

What is the current behavior?

A race condition exists when showing a view modally on ios if that view has been assigned width and height. In _showNativeModalView (@nativescript/core/ui/core/view/index.ios.ts, 459) const controller is assigned the value this.viewController. In the handler callback created on line 481, the width/height from the view are assigned to the preferredContentSize of the controller. However at the conclusion of _showNativeModalView, the controller variable is released, creating a race condition for the handler.

What is the new behavior?

Making the perferredContentSize assignment on this.viewController instead of controller avoids a race condition.

[nx-cloud]

Nx Cloud Report

CI is running for commit e52e8f9.

📂 Click to track the progress, see the status, the terminal output, and the build insights.

---

Sent with 💌 from NxCloud.

[AdamAtri]

Rock on!!! My first commit to {N} core!