[MD] Data source picker should have same behavior in devtool, tutorial, etc where it is used

[BionIT]

Is your feature request related to a problem? Please describe.

I feel confused when seeing different behavior for the data source picker based on where it is located

Describe the solution you'd like

The datasource picker should be one component to ensure the behavior is the same. Then, if we need to change the behavior for the picker, we don't need to go through entire code base to find the duplicated code in order to make change. The component should be reusable by other plugins
To unify the behavior, the default option for the picker when first opening the page with the picker should be Local cluster. After removing the option, it should display Select a data source. Change the DataSource to Data source

Describe alternatives you've considered

Stay where we are and just change every places every time that a small text adjustment is needed for the picker.

Additional context
When data source plugin is enabled, if we go to dev tool page or add sample data page, the behavior of the data source picker is different:

• dev tools shows Select a data source and the prepend is Data source
  

• add sample data tutorial shows a default value and the prepend is DataSource
  
  after removing the default value it shows Select a Data Source
  

[BionIT]

Happy to work on it

[bandinib-amzn]

After removing the option, it should display Select a data source. Change the Data source or DataSource to Destination

Does that mean all occurrences of Select a data source will change to Select a destination?

[bandinib-amzn]

Adding here some feedback I received from UX team while reviewing these pages:

1. Make first created data source as default data source and set default data source as default selected option on dev tool and sample data screens instead of Select a data source.

2. On Dev Tool, Sample Data screens, use the new data source picker component. [Feature] Datasource selector of multiple datasources  #5167. We need to figure out if we can filter out index patterns and only show data sources.

3. Ideally when no data source present on dev tool, sample data (and there is no local cluster), it should instruct user to create data source first. We need similar experience when we visit dashboards, visualization, discover and no index pattern has been created.

[BionIT]

After removing the option, it should display Select a data source. Change the Data source or DataSource to Destination

Does that mean all occurrences of Select a data source will change to Select a destination?

Yeah, you are right, it should be Select a destination

Make first created data source as default data source and set default data source as default selected option on dev tool and sample data screens instead of Select a data source.

At of today, in my understanding, local cluster has to be present unless #5696 is introduced

On Dev Tool, Sample Data screens, use the new data source picker component. [Feature] Datasource selector of multiple datasources #5167. We need to figure out if we can filter out index patterns and only show data sources.

I can consult UX about this component, my feeling is it is too busy to show a label inside the picker where we already know we are looking for datasource instead of any other objects.

Ideally when no data source present on dev tool, sample data (and there is no local cluster), it should instruct user to create data source first. We need similar experience when we visit dashboards, visualization, discover and no index pattern has been created.

This behavior doesn't exist yet until local cluster can be removed, and agree that the behavior should be the same, and we can decide later if the behavior should be implemented in the picker