feat: enable feedback button on nightly releases (#8220)

## Summary

Enables the feedback button on nightly releases to collect user feedback
and distinguish it from stable releases in Zendesk.

## Changes

- Add distribution tracking to feedback URL (cloud/nightly/stable)
- Export `getDistribution()` and `ZENDESK_FIELDS` from support config
for reuse
- Enable feedback button for both cloud and nightly builds
- Track distribution in Zendesk as: `ccloud`, `oss-nightly`, or `oss`
- Fix type signatures for `normalizeIndustry`/`normalizeUseCase` to
accept `unknown`

## Requirements

- [ ] Support team needs to add `oss-nightly` as a valid value for the
distribution field in Zendesk

## Test plan

- [ ] Build and run nightly version, verify feedback button appears
- [ ] Click feedback button, verify Zendesk form opens with correct
distribution parameter
- [ ] Verify cloud builds still show feedback button as before
- [ ] Verify stable OSS builds don't show feedback button

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8220-feat-enable-feedback-button-on-nightly-releases-2ef6d73d3650816db81ef970919770a4)
by [Unito](https://www.unito.io)

src/extensions/core/index.ts

@@ -32,13 +32,17 @@ if (isCloud) {
   await import('./cloudRemoteConfig')
   await import('./cloudBadges')
   await import('./cloudSessionCookie')
-  await import('./cloudFeedbackTopbarButton')
 
   if (window.__CONFIG__?.subscription_required) {
     await import('./cloudSubscription')
   }
 }
 
+// Feedback button for cloud and nightly builds
+if (isCloud || isNightly) {
+  await import('./cloudFeedbackTopbarButton')
+}
+
 // Nightly-only extensions
 if (isNightly && !isCloud) {
   await import('./nightlyBadges')