This integration test fails intermittently because we're not (correctly)
awaiting the character limit increase sandbox action.
For the first increase an attempt was made to handle this, but it doesn't
work correctly because the text in the field is `abcdefghijklmnopq` and
it's not be truncated until the sandbox action is completed, so because
we didn't await that we would could pass the `value !== "abcdefgh"` check
because `abcdefghijklmnopq !== abcdefgh` is true. For the second increase
we didn't have a check in place.
This commit fixes the issues by using the `waitForSandboxTrip` and
`waitForSelector` helper functions to make sure that we can only proceed
if the sandbox action is completed and the DOM element is updated.