unboound_variable remove last error

poc

@@ -338,6 +338,7 @@ function on_exit {
         failure_type='UNBOUND_VARIABLE'
         failure_payload=$payload
 
+        unset 'tmp_error[-1]'
         add_miaou_error "${BASH_SOURCE[1]}" "${BASH_LINENO[0]}" "${failure_code}" "${failure_type}" "${failure_payload}"
         miaou_debug "<unbound_variable source=${source} line=${line} payload={${failure_payload}}/>"
       else