Deprecate VelocityTracker default constructor and added VelocityTracker.withKind constructor (#66043)

We've gotten feedback that the VelocityTracker change was disruptive, though it did not break any of the flutter framework or customer tests. In order to make the change non-breaking, PointerDeviceKind parameter can be made optional.

Nevertheless, this parameter should be provided so that the existing touch handlers can use more accurate gestures on mouse/stylus inputs, so we can encourage this by deprecating the default constructor and pointing users towards the VelocityTracker.withKind constructor that takes a non-optional parameter

PR #65873 enabled DDS for non-web Flutter applications. This change
surfaced a bug where DDS would not send ServiceRegistered events to VM
service clients when they subscribed to the Service stream. This would
cause tools and tests that rely on these events (e.g., hot reload in
VSCode) to fail.

Fixes #66038.

This reverts commit cb92ffc7.

This reverts commit 10a66b19.

This reverts commit fd0554ba.

If a new service worker is installed, automatically update this behind the scenes. Immediately after a page refresh, the new worker and cache will be available, though the main.dart.js and others will be available sooner due to the cache busting URLS

This reverts commit 66b01c1f.

* Add DDS ipv6 support

* Use --dds-port for DDS instead of hijacking --host-vmservice-port

Fix a bug in the layout of some textfields with constrained height and visual density.

Expose GestureBinding.handlePointerEvent, replacing dispatchEvent as the preferred way to dispatch events (#64846)

Fix the `character` field of the `RawKeyEvent` to hold correct data on non-Android platforms. (#65667)

This fixes a problem where the character field of the RawKeyEvent was not being set at all for non-Android platforms.

I also updated the key maps, and corrected a problem with the Windows key map where the backquote character wasn't correctly mapped.