Update widget_toolkit ecosystem dependencies

[DavidDWiser]

While testing out the rx_bloc_cli generated project build and deploy pipeline, several errors were thrown resulting in a failed pipeline. After some research, it turned out that a dependency (app_settings, specifically version 5.2.0) was causing them.

Update the package dependencies so they resolve this issue.

Dev Note: This specific version (and above) contains the fix for the iOS issue.