Unhelpful logging in `/api/v1/auth/saml/{name}/response/`

[sentry]

Sentry Issue: FLAGSMITH-API-5GX

SAML response code=None for organisation=21082: Failed to verify signature

[sentry]

Sentry Issue: FLAGSMITH-API-5GV

[sentry]

Sentry Issue: FLAGSMITH-API-5GW

[sentry]

Sentry Issue: FLAGSMITH-API-5GT