[plugins] better string handling (#4198)
[plugins] better string handling (#4198)

- strip surrounding whitespace
- validate for empty strings when required
looker/sentry,looker/sentry,ifduyue/sentry,looker/sentry,zenefits/sentry,BuildingLink/sentry,mvaled/sentry,BuildingLink/sentry,ifduyue/sentry,jean/sentry,fotinakis/sentry,jean/sentry,JamesMura/sentry,mvaled/sentry,looker/sentry,BuildingLink/sentry,zenefits/sentry,fotinakis/sentry,gencer/sentry,JamesMura/sentry,jean/sentry,fotinakis/sentry,ifduyue/sentry,mvaled/sentry,JamesMura/sentry,mvaled/sentry,looker/sentry,fotinakis/sentry,zenefits/sentry,JamesMura/sentry,jean/sentry,alexm92/sentry,JackDanger/sentry,zenefits/sentry,alexm92/sentry,beeftornado/sentry,mvaled/sentry,alexm92/sentry,BuildingLink/sentry,jean/sentry,gencer/sentry,ifduyue/sentry,JackDanger/sentry,gencer/sentry,beeftornado/sentry,JamesMura/sentry,mvaled/sentry,BuildingLink/sentry,zenefits/sentry,gencer/sentry,gencer/sentry,ifduyue/sentry,beeftornado/sentry,JackDanger/sentry