[Data plugin] Wrong caching for Index pattern fields

[alexwizp]

Kibana version:
master

Describe the bug:
While working on #84336 I encountered strange caching of the pattern index fields on the server side of Kibana.
To reproduce this issue please checkout #84612

Steps to reproduce:

1. Install some of Sample Data

2. Go to Stack Management -> Index patterns -> your index (e.g. kibana_sample_data_ecommerce)

3. Set custom label for some field (e.g. order_date -> 'custom label (order date)')
   

4. After saving go to TSVB and try to select somewhere field from step 3
   

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Expected behavior:
I expect to see custom label (order date)

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5. To be sure this isn't a UI issue, let's reload the entire page and open
   

6. Now let's restart Kibana server. Custom label was applied
   

[elasticmachine]

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

[mattkime]

I took a look but I'm having trouble reproducing the problem. As best I can tell any changes made in the index pattern saved object are reflected after saving in index pattern management and navigating to TSVB

[stratoula]

@mattkime I have the same problem. I change the label of a field and when I am trying to use it on TSVB I can't see the label. If I restart the server everything works fine