Adding optional Encounter Type Parameter to ObsGraph Widget

Background

In one of our requirement, we are showing multiple graphs based on observations. For that we are using ObsGraph.

In our scenario, we have same concept used in multiple encounter types (for example custom concept 'Total Score' is used in multiple encounter types). Due to this, we are seeing `Total Score` observations from different encounter types are shown in same graph.

So want to have filter based on EncounterType for ObsGraph.

Expected Change

We wish to implement optional filter parameter for encounterType in ObsGraph Widget.

ObsGraph should work as expected even encounterType is not configured.

{
  "id": "coreapps.obsGraph",
  "instanceOf": "coreapps.template.dashboardWidget",
  "description": "coreapps.obsGraph.app.description",
  "order": 10,
  "config": {
    "widget": "obsgraph",
    "icon": "icon-bar-chart",
    "label": "Obs Graph",
    "conceptId": "5090AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA,3ce93cf2-26fe-102b-80cb-0017a47871b2",
    "maxResults": "6",
    "maxAge": "1w",
    "encounterType": "45693cf2-22ge-102b-80cb-0017a47812d2"
  },
  "extensions": [
    {
      "id": "org.openmrs.module.coreapps.mostRecentVitals.clinicianDashboardFirstColumn",
      "appId": "coreapps.obsGraph",
      "extensionPointId": "patientDashboard.firstColumnFragments",
      "extensionParams": {
        "provider": "coreapps",
        "fragment": "dashboardwidgets/dashboardWidget"
      }
    }
  ]
}