State: update Array.find usage to use lodash

[gwwar]

This fixes an Array.find usage. We don't have a full polyfill solution for prototype methods (see #6117 ) so this will break in IE

Testing Instructions

• Test pass
• Navigate to http://calypso.localhost:3000/purchases
• No warnings are thrown while cancelling a purchase

cc @yurynix

Test live: https://calypso.live/?branch=fix/ie-find

[yurynix]

Live branch failing for me.

cc @Tug

[Tug]

Thanks for notifying me @yurynix. I had to remove the branch manually on the server because of this node-sass error. I often have this error myself locally and have to remove the dependency manually to make it work again...

[yurynix]

I've checked that branch locally, looks good to me 👍

[gwwar]

Thanks for the reviews and merge!