Add support for deep links with fragmented activity

[jan-milovanovic]

• Check for existing deep link paths for FlutterFragmentActivity and add it to inital route if it exists
• Additionally, bump version and fix text themes for examples as suggested by dart analyzer.

Fixes #1029

Pre-launch Checklist

• [x] I read the CONTRIBUTING.md and followed the process outlined there for submitting PRs.
• [x] My change is not breaking and lands in minor branch OR my change is breaking and lands in major branch.
• [x] If I'm the first to contribute to the next version, I incremented the version number in pubspec.yaml according to the pub versioning philosophy.
• [x] I updated CHANGELOG.md to add a description of the change (format: * DESCRIPTION OF YOUR CHANGE (@your-git-username)).
• [😶] I updated/added relevant documentation (doc comments with ///).
• [x] I ran dart analyze.
• [x] I ran dart format.
• [x] I ran flutter test and all tests are passing.