Moved execution params to destructuring
Moved execution params to destructuring

A change in the library fulfillment means `execution.params` may be undefined
For each command one needs to explicitly say params is defined

See https://github.com/actions-on-google/actions-on-google-nodejs/commit/1c9c56b1e837a7cc54bd1c8058d3ddbe2747863b

Change-Id: Ie4469e068c77c92325882ba58fdf1573fdd466c8

actions-on-google/smart-home-nodejs,actions-on-google/smart-home-nodejs