test: Use to-existing-root --acknowledge-destructive

In the test suite, pass the --acknowledge-destructive flag to `bootc
install to-existing-root` to avoid the 20 second timer.

Signed-off-by: Evan Goode <[email protected]>

Author: evan-goode

tmt/tests/test-00-bootc-install.sh

@@ -126,7 +126,7 @@ REALEOF
         -v /root/.ssh:/output \
         --security-opt label=type:unconfined_t \
         "localhost/bootc:tmt" \
-        bootc install to-existing-root --target-transport containers-storage
+        bootc install to-existing-root --target-transport containers-storage --acknowledge-destructive
 
     # Reboot
     tmt-reboot