saleforce remove flatten from lodash

[mtuchi]

Description
The salesforce adaptor uses flatten from lodash. See L103 in execute() function , We should remove this since it's an old implementation or add our own implementation of flatten in util

Eg:

function flatten(array) {
  return [].concat(...array);
  // or using flat()
  // return array.flat(1);
}

[aleksa-krolls]

@mtuchi is this spec ready to go? And should this be considered for the next sprint and moved to Sprint Candidates?

Or are you just adding it to the epic to consider for later? cc @martalovescoffee

[josephjclark]

Just adding to consider. I'll take a quick look to make sure this is the right thing to do