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?

Right now, there are cases when views lose some of their visual states because only a single visual state is supported at a time.

What is the new behavior?

This PR ensures that a view may own multiple visual/pseudo states at the same time.
Added _addVisualState and _removeVisualState private methods and deprecated _goToVisualState private method to achieve this.
New methods will internally add/remove defaultVisualState when needed.
On top of that, existing event listeners were improved and added automated tests for new methods as well.

These changes were inspired from #9789 even though they have not included any new public API for modifying view pseudo-states so let's leave the issue open.