west: runners: add option 'v' prefix to OpenOCD version string

The Espressif branch of OpenOCD uses the version string "v0.12.0" instead
of "0.12.0" causing the version regex match to fail.

Add an optional 'v' prefix to avoid the failure.

Fixes: #83373
Signed-off-by: Eric Holmberg <eric.holmberg@northriversystems.co.nz>