[Discover] Inline shard error warnings

[kertal]

When there's a shard error in Discover, it is displayed as a toast.

We recently switched errors to be rendered inline in

#152311

Warnings like the inline shard error one should be rendered similar to the banner style of an error message (but as a warning, so yellow)

The same should apply to warning when rendering saved searches on a dashboard, because shard errors are also displayed with toasts:

In development mode it can be simulated by instlling all our demo data, create a data view with the index pattern kibana* without timestamp, and replace

kibana/src/plugins/data/common/search/search_source/search_source.ts

Line 917 in 2406ada

body.query = buildEsQuery(index, query, filters, esQueryConfigs);

with

// body.query = buildEsQuery(index, query, filters, esQueryConfigs);
    body.query = {
      error_query: {
        indices: [
          {
            name: 'kibana_sample_data_ecommerce',
            shard_ids: [0, 1],
            error_type: 'exception',
            message: 'Everythings is fine! I swear!',
          },
          {
            name: 'kibana_sample_data_logs',
            shard_ids: [0, 1],
            error_type: 'exception',
            message: 'Next time I return results! I swear!',
          },
        ],
      },
    };

This triggers a shard error

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)