[UX-234] make the slideup animation nicer
[UX-234] make the slideup animation nicer

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