Fix touch event conversion bugs. (#19780)

These are bugs uncovered by the integration test for embedded Android
views:

  * Some PointerEvents were constructed with radiusMinor set to
  radiusMajor.
  * Some PointerEvents were missing radiusMajor/radiusMinor.
  * The pressure parameter was not passed to PointerUpEvent.
  * radiusMin, radiusMax, radiusMinor, and radiusMajor were not
  converted from physical pixels to logical.

Sending the fixes without a test as the bugs are covered by the integration
test that is going to land soon.