[Cashtab] Do not clearTimeout when alias component unmounts
Summary:
Since this is a timeout, and not an interval, we are only clearing one possible extra call.
In testing, this clearance is not working. So, stop trying to do this.
Test Plan: npm test
Reviewers: #bitcoin_abc, emack
Reviewed By: #bitcoin_abc, emack
Differential Revision: https://reviews.bitcoinabc.org/D15337