small fix: fix test fixture and add a clarifying comment to the mutator

Author: anton-107

acceptance/bundle/deploy/dashboard/test.toml

@@ -28,7 +28,7 @@ Response.Body = '''
     "dashboard_id":"1234567890abcdef1234567890abcdef",
     "display_name": "test dashboard 6260d50f-e8ff-4905-8f28-812345678903",
     "lifecycle_state": "ACTIVE",
-    "path": "/Users/[USERNAME]/test bundle-deploy-dashboard [UUID].lvdash.json",
+    "path": "/Users/[USERNAME]/test bundle-deploy-dashboard 6260d50f-e8ff-4905-8f28-812345678903.lvdash.json",
     "parent_path": "/Users/tester@databricks.com",
     "serialized_dashboard": "{\"pages\":[{\"name\":\"02724bf2\",\"displayName\":\"Dashboard test bundle-deploy-dashboard\"}]}"
 }

bundle/config/mutator/resourcemutator/configure_dashboards_serialized_dashboard.go

@@ -38,7 +38,7 @@ func (c configureDashboardSerializedDashboard) Apply(_ context.Context, b *bundl
 		return dyn.MapByPattern(v, pattern, func(p dyn.Path, v dyn.Value) (dyn.Value, error) {
 			// Include "serialized_dashboard" field if "file_path" is set.
 			// Note: the Terraform resource supports "file_path" natively, but we read the contents of the dashboard here
-			// to cover the use case of deployments from the workspace
+			// to be able to read file contents in Databricks Workspace (reading a dashboard file via file system fails there)
 			path, ok := v.Get(filePathFieldName).AsString()
 			if !ok {
 				return v, nil