fix(saml): enforce only POST request on ACS view
fix(saml): enforce only POST request on ACS view

Fixes SENTRY-4BD

mvaled/sentry,gencer/sentry,ifduyue/sentry,mvaled/sentry,ifduyue/sentry,gencer/sentry,mvaled/sentry,ifduyue/sentry,mvaled/sentry,gencer/sentry,beeftornado/sentry,ifduyue/sentry,mvaled/sentry,looker/sentry,ifduyue/sentry,gencer/sentry,looker/sentry,looker/sentry,looker/sentry,beeftornado/sentry,beeftornado/sentry,mvaled/sentry,looker/sentry,gencer/sentry