Solving the alert race condition

[brickpop]

This PR is final

• Solves the case where dismissing one alert while another was ongoing would provoke a race condition
• The main change is on context/Alert.tsx. The rest are just a rename to a more sensible term

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Jør∂¡ seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}