Alert types can have two names

[mikecote]

I noticed you can name an alert type differently in the backend as you can in the front end. We should have a single place to define this name.

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[mikecote]

I noticed in my PR I had to rename two areas for the same alert type:

1. https://github.com/elastic/kibana/pull/61693/files#diff-7e4d7d860aa7fdacfe4970ba2cf1d60f
2. https://github.com/elastic/kibana/pull/61693/files#diff-73a468493f7c4445fab5106fd6f92e27

[mikecote]

To support custom headers (https://github.com/elastic/kibana/pull/64753/files#diff-b09601a46b1e08b630ba6fb679076febR107) we can make the UI name optional and accept JSX.Element only. We can pass down the server side name to the component so they don't have to define it twice.