* Trigger overlay prompt when focusing on username field
* Adjust accessibility overlay position in response to scroll events
* Get username EditText with a single pass of the node tree, plus additional cleanup
* UI support in app settings for handling overlay permission requirement in Accessibility Service implementation
* Cleaned up shorthand operator with new var
* Replaced accessibility service notification with in-line overlay. Requires draw-over permission to be enabled (will prompt if not, though this will be enhanced in subsequent commits)
* Updated with requested changes
* Fix for FDroid build
AccessibilityNodeInfo.FindAccessibilityNodeInfosByViewId(..) returns
null when the source package is a supported browser, return a null
uri to prevent overwriting the existing notification's pendingIntent
uri extra with the brower's packageName.
* AccessibilityService.cs: Added null uri checks as it is now possible
for AccessibilityHelpers.getUri(..) to return a null uri when the
Accessibility Service is misbehaving.
