Website: Update values to match CRM picklist values (#38734)

Changes:
- Updated the accepted `intentSingal` values in the receive-from-clay
webhook and the createHistoricalEvent helper to match the picklist
values in Salesforce
- updated a "most recent/source channel details" value set in the
updateOrCreateContactAndAccount helper to match the picklist value in
Salesforce.

website/api/controllers/webhooks/receive-from-clay.js

@@ -59,7 +59,7 @@ module.exports = {
         'Fleet channel member in MacAdmins Slack',
         'Fleet channel member in osquery Slack',
         'Implemented a trial key',
-        'Signed up Fleet event',
+        'Signed up for Fleet event',
         'Engaged with Fleetie at event',
         'Attended a Fleet happy hour',
         'Stared the fleetdm/fleet repo on GitHub',