Use ffx to find Fuchsia version

Use ffx in fuchsia_device.py to find version numbers on running devices.

The cat command line tool is not always available in SSH sessions. In
fact, there's a push away from using SSH across the project. The ffx
host side command line tool is the currently recommended path forward.

Bug: 230903682
Fix: 230903682
Test: act.py [...] -tc FlashTest
Change-Id: Ifdb522e6a3523df641725eef7b4a7e84374f679a
1 file changed
tree: d2036686b3f65500a970aae17aca8385bd93483e
  1. acts/
  2. acts_tests/
  3. tools/
  4. wts-acts/
  5. Android.mk
  6. LICENSE
  7. OWNERS
  8. PREUPLOAD.cfg