PLT-7: Refactoring api to use translations (chunk 4)

- Translation for api templates english and spanish

api/templates/verify_subject.html

@@ -1 +1 @@
-{{define "verify_subject"}}[{{ .Props.TeamDisplayName }} {{ .ClientCfg.SiteName }}] Email Verification{{end}}
+{{define "verify_subject"}}{{.Props.Subject}}{{end}}