[UX-407] control dismiss of Toast via state variable; better more React-like semantics
[UX-407] control dismiss of Toast via state variable; better more React-like semantics

kzantow/blueocean-plugin,alvarolobato/blueocean-plugin,alvarolobato/blueocean-plugin,jenkinsci/jenkins-design-language,alvarolobato/blueocean-plugin,jenkinsci/blueocean-plugin,cliffmeyers/jenkins-design-language,kzantow/blueocean-plugin,kzantow/blueocean-plugin,jenkinsci/blueocean-plugin,jenkinsci/jenkins-design-language,cliffmeyers/jenkins-design-language,alvarolobato/blueocean-plugin,jenkinsci/blueocean-plugin,cliffmeyers/jenkins-design-language,jenkinsci/blueocean-plugin,kzantow/blueocean-plugin,jenkinsci/blueocean-plugin