Migrated tag cloud from 5.6.16 displays error in 7.10/7.11

[bhavyarm]

Kibana version: 5.6.16->7.10.0/7.11.0

Elasticsearch version: 5.6.16->7.10.0/7.11.0

Server OS version: darwin_x86_64

Browser version: chrome latest

Browser OS version: OS X

Original install method (e.g. download page, yum, from source, etc.): from staging

Describe the bug: Tag cloud saved object (migrated from 5.6.16) errors out on the display in 7.10/7.11

Steps to reproduce:

1. Get 5.16.16 stack up - ingest load sample logstash data from here (https://www.elastic.co/guide/en/kibana/5.6/tutorial-load-dataset.html)
2. Create a tag cloud with logstash data - I used geo.src.keyword -
3. Use the upgrade assistant and then do a rolling upgrade to 6.8.13 - tag cloud opens without any problems
4. Do a rolling upgrade from 6.8.13 to 7.10.0/7.11.0 - tag cloud displays error

I have attached the saved json to the bug - export_tag_cloud.json.txt

Search Error

Unknown argument 'type' passed to function 'tagcloud'

Error: Unknown argument 'type' passed to function 'tagcloud'
at http://localhost:5601/36580/bundles/plugin/expressions/expressions.plugin.js:1:67601
at http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:6364
at http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:28176
at lr (http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:17621)
at http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:27981
at Tt (http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:6330)
at On.reduce (http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:421:62551)
at _callee4$ (http://localhost:5601/36580/bundles/plugin/expressions/expressions.plugin.js:1:67460)
at l (http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:321:1751401)
at Generator._invoke (http://localhost:5601/36580/bundles/kbn-ui-shared-deps/kbn-ui-shared-deps.js:321:1751154)

Screenshots (if relevant):

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[elasticmachine]

Pinging @elastic/kibana-app-services (Team:AppServices)

[pgayvallet]

Forwarding to @elastic/kibana-app-services as the error is thrown from the expression plugin. Seems like it might be that the registered SO migrations for the type from 5.6.16 to 7.10.0 might be in cause, at it seems the object is in an invalid state on 7.10.0

[lukeelmers]

The error that's coming from the expressions service suggests that the tagcloud expression function is receiving an unexpected type argument. This makes sense, as the visState from the migrated saved object appears to have "type" duplicated in the params, and the params are passed straight through to the expression function in tagcloud's to_ast.ts:

{
  "title": "tag_cloud",
  "type": "tagcloud",
  "params": {
    "scale": "linear",
    "orientation": "single",
    "minFontSize": 18,
    "maxFontSize": 72,
    "type": "tagcloud" // <-- This is what's causing the error
  },
  "aggs": [...],
  "listeners": {...}
}

cc @sulemanof -- I wonder if this was an accidental regression from #77910, as the 7.9 implementation of build_pipeline was picking specific args to include in the tagcloud expression function, whereas the 7.10 to_ast implementation just passes through whatever params are on the vis.

A shorter-term fix would be explicitly pulling out the known args inside to_ast, but longer term it would be worth considering a SO migration to remove the unneeded type from the params.