fix(ios): ActionBar style wrong after cancelled swipe back navigation

[vakrilov]

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/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/DevelopmentWorkflow.md#running-unit-tests.
• Tests for the changes are included - https://github.com/NativeScript/NativeScript/blob/master/WritingUnitTests.md.

What is the current behavior?

If swipe back navigation is cancelled - the current page ActionBar gets the style from the previous page in the nav-stack (the one that we were swiping back to).

What is the new behavior?

If the swipe back navigation is cancelled - the current style of the ActionBar is preserved.

Fixes: #7430

[vakrilov]

@dtopuzov e2e test needed and can be implemented in the e2e/ui-test-app.
Here are the steps:

1. Go to actBG page
2. Action bar is green
3. Click the go to cleared page
4. Action bar is white again
5. Start swipe-back navigation form the left of the screen, but then cancel
6. Validate: The navigations stays on the same page and the action bar remains white (without the fix it turns green as it wrongly takes the styles from the previous page)

[dtopuzov]

test --ignore