Kibana displays empty panels for certain saved search panels in dashboard for imported dashboards

[bhavyarm]

Kibana version: 7.12.0 BC1

Elasticsearch version: 7.12.0 BC1

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: If user imports a dashboard from 6.8.x to 7.12 and that dashboard has saved searches - Kibana displays empty panels for certain saved search panels.

The same dashboard displays correctly in 7.11.1.
I am attaching the saved objects in a .txt file. They are built out of shakespeare and logstash. I used esarchiver to ingest the data

node scripts/es_archiver load logstash_functional --config test/functional/config.js  --es-url=http://localhost:9200 --kibana-url=http://localhost:5601
node scripts/es_archiver load getting_started/shakespeare --config test/functional/config.js  --es-url=http://localhost:9200 --kibana-url=http://localhost:5601

Steps to reproduce:

1. Get ES/Kibana 7.12 stack up
2. Run the esarchiver in your kibana dev directory to load the data (please note you can reproduce this with sample data saved objects too)
3. import the attached json
4. shakespeare dashboard displays empty saved search panels for "shakespeare_saved_search" & "shakespeare_kql_search"
5. The same searches work fine in discover

Please note attached saved json contains logstash saved objects too.

Saved objects JSON:
6.8._import_objects.json.txt

Screenshots (if relevant):

Dashboard display in 7.12.0 with empty panels for saved searches:

The saved searches in discover where results are getting displayed in 7.12.0:

Same dashboard in 7.11.1 with non-empty search panels:

Dashboard display in 6.8.14:

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[kertal]

I've tested this in master which contains lot's of related changes (#88426) back ported to 7.12 and it works (using _source and using fields), so it should be fixed with BC2, let's revisit it once the next build is available

[flash1293]

#91987 Should take care of that, but we can verify with the next BC

[bhavyarm]

This is fixed in BC2 closing. Thanks @kertal @flash1293