fix(ui): fixed width button. Fixes #4973

[tczhao]

Fixes #4973

https://fontawesome.com/v5.15/how-to-use/on-the-web/styling/fixed-width-icons

Untitled_.Oct.7.2021.8_27.PM.mp4

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[codecov]

Codecov Report

Merging #6883 (d679a79) into master (689ad68) will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #6883      +/-   ##
==========================================
- Coverage   48.55%   48.50%   -0.05%     
==========================================
  Files         265      265              
  Lines       19220    19250      +30     
==========================================
+ Hits         9332     9337       +5     
- Misses       8839     8860      +21     
- Partials     1049     1053       +4     

Impacted Files	Coverage Δ
workflow/metrics/server.go	15.78% <0.00%> (-3.51%)	⬇️
cmd/argoexec/commands/emissary.go	50.35% <0.00%> (-1.44%)	⬇️
pkg/apiclient/http1-client.go	0.00% <0.00%> (ø)
pkg/apiclient/argo-kube-client.go	0.00% <0.00%> (ø)
pkg/apiclient/argo-server-client.go	0.00% <0.00%> (ø)
pkg/apiclient/offline-workflow-service-client.go	0.00% <0.00%> (ø)
...ient/argo-kube-workflow-template-service-client.go	0.00% <0.00%> (ø)
.../error-translating-cron-workflow-service-client.go	0.00% <0.00%> (ø)
server/workflow/workflow_server.go	46.80% <0.00%> (+2.39%)	⬆️

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