Fix #8009: Update toolbar constraints to utilize safe area properly

[kylehickinson]

The value of UIApplication.shared.keyWindow?.safeAreaInsets.bottom is not updated when the updateViewConstraints method is called. However calculating this height manually is not correct/not needed, as we can simply rely on the safe area layout guides

Bonus: UIApplication.shared.keyWindow is actually deprecated, so 1 less usage of this now exists in the codebase

Summary of Changes

This pull request fixes #8009

Submitter Checklist:

• Unit Tests are updated to cover new or changed functionality
• User-facing strings use NSLocalizableString()
• New or updated UI has been tested across:
  • Light & dark mode
  • Different size classes (iPhone, landscape, iPad)
  • Different dynamic type sizes

Reviewer Checklist:

• Issues include necessary QA labels:
  • QA/(Yes|No)
  • bug / enhancement
• Necessary security reviews have taken place.
• Adequate unit test coverage exists to prevent regressions.
• Adequate test plan exists for QA to validate (if applicable).
• Issue and pull request is assigned to a milestone (should happen at merge time).