[ML] Transforms: Update functional test assertion, reenable tests. (e…

…lastic#176920)

## Summary

Fixes elastic#151889
Fixes elastic#151811
Fixes elastic#176697
Fixes elastic#176698
Fixes elastic#176865

Updates assertions after ES snapshot promotion and reenables tests.

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

(cherry picked from commit 21ca904)

x-pack/test/functional/apps/transform/creation/index_pattern/creation_index_pattern.ts

@@ -223,7 +223,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
             {
               chartAvailable: true,
               id: 'customer_full_name',
-              legend: 'top 20 of 3321 categories',
+              legend: 'top 20 of 3327 categories',
               colorStats: [
                 { color: '#000000', percentage: 25 },
                 { color: '#54B399', percentage: 75 },