watchcat: add optional failure timer reset

watchcat: add optional failure timer reset

Add an opt-in reset_failure_timer option for restart_iface and
run_script modes.

When enabled, watchcat starts a fresh failure window after the
recovery action finishes before allowing another recovery action.
The existing behavior remains the default.

Document the intended default and reset_failure_timer timing
behavior in TIMINGS.md and use a safer string comparison for the
reset_failure_timer check.

Signed-off-by: Dharmik Parmar <redacted>