SAML: Only show SAML login button on Enterprise version (#18270)

SAML Authentication is an Enterprise only feature. This change enables
the SAML login button to only be shown on enterprise.

pkg/api/login.go

@@ -44,7 +44,7 @@ func (hs *HTTPServer) LoginView(c *models.ReqContext) {
 	viewData.Settings["loginHint"] = setting.LoginHint
 	viewData.Settings["passwordHint"] = setting.PasswordHint
 	viewData.Settings["disableLoginForm"] = setting.DisableLoginForm
-	viewData.Settings["samlEnabled"] = hs.Cfg.SAMLEnabled
+	viewData.Settings["samlEnabled"] = setting.IsEnterprise && hs.Cfg.SAMLEnabled
 
 	if loginError, ok := tryGetEncryptedCookie(c, LoginErrorCookieName); ok {
 		//this cookie is only set whenever an OAuth login fails