Fix Navigation Dismantle Crash When Unmounting Navigation Screen

[Victor-Andrade]

This PR fixes an EXC_BAD_ACCESS crash occurring when unmounting a screen that uses our custom navigation library.

Error Explanation:
The crash was triggered in the dismantleUIViewController method. The issue stemmed from two points:

• An unnecessary try was used on a non-throwing assignment to navigation.viewControllers.
• A forced cast (as! PopAwareUINavigationController) was used, which could lead to memory access issues if the object was not of the expected type.

Solution:

• Removed the redundant try.
• Replaced the forced cast with a conditional cast (as? PopAwareUINavigationController).
• Ensured that UI updates occur on the main thread.

These changes prevent invalid memory access and improve the stability.