examples: rewrite vision_odometry as ground truth feedback loop

Rewrites the vision odometry example to use a ground truth feedback
approach: reads the drone's actual position in simulation, adds
configurable noise and delay, and feeds it back as vision odometry.
The drone takes off and hovers while the VIO feed runs, showing
real-time EKF2 fusion status.

Uses new Odometry fields (reset_counter, estimator_type, quality)
from MAVSDK-Proto PR #395 / MAVSDK PR #2791. Includes a startup
validation that prints a clear error if these fields are not yet
available.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: alireza787b