fix: remove work/personal onboarding telemetry (#24021)

Following on from #23989 #24018 

- We also no longer want to collect `IsBusiness` demographic data
- Newsletter fields no longer allow `nil` as a value, instead default to
false

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

coderd/apidoc/docs.go

@@ -14586,9 +14586,6 @@ const docTemplate = `{
         "codersdk.CreateFirstUserOnboardingInfo": {
             "type": "object",
             "properties": {
-                "is_business": {
-                    "type": "boolean"
-                },
                 "newsletter_marketing": {
                     "type": "boolean"
                 },

coderd/apidoc/swagger.json

@@ -13126,9 +13126,6 @@
 		"codersdk.CreateFirstUserOnboardingInfo": {
 			"type": "object",
 			"properties": {
-				"is_business": {
-					"type": "boolean"
-				},
 				"newsletter_marketing": {
 					"type": "boolean"
 				},