Opening video from video preset inspector throws null reference exception.

Steps to repro:
1. Create a new project.
2. Drag any .mp4 file into the project view of the project.
3. Create preset of the video file.
5. Select preset in the project view.
6. Click on Open.

Actual Result:
Null Reference exception is thrown.

Expected Result:
The open button is disabled.

Environment:
Windows and Mac

Occurring with:
2019.3.0a3, 2019.3.0a1

Working fine:
2019.2.0b3

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.AssetDatabase.OpenAsset (UnityEngine.Object[] objects) (at /Users/builduser/buildslave/unity/build/artifacts/MacEditor/modules/Editor/AssetDatabaseBindings.gen.cs:351)
UnityEditor.VideoClipImporterInspector.OnHeaderControlsGUI () (at /Users/builduser/buildslave/unity/build/Modules/AssetPipelineEditor/ImportSettings/VideoClipImporterInspector.cs:704)
UnityEditor.Editor.DrawHeaderGUI (UnityEditor.Editor editor, System.String header, System.Single leftMargin) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:867)
UnityEditor.Editor.DrawHeaderGUI (UnityEditor.Editor editor, System.String header) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:854)
UnityEditor.Editor.OnHeaderGUI () (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:747)
UnityEditor.Editor.DrawHeaderFromInsideHierarchy () (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:848)
UnityEditor.Editor.DrawHeader () (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/Editor.cs:704)
UnityEditor.Presets.PresetEditor.DrawInternalInspector () (at /Users/builduser/buildslave/unity/build/Modules/PresetsEditor/PresetEditor.cs:207)
UnityEditor.Presets.PresetEditor.DrawPresetData () (at /Users/builduser/buildslave/unity/build/Modules/PresetsEditor/PresetEditor.cs:92)
UnityEditor.Presets.PresetEditor.OnInspectorGUI () (at /Users/builduser/buildslave/unity/build/Modules/PresetsEditor/PresetEditor.cs:80)
UnityEditor.UIElements.InspectorElement+<CreateIMGUIInspectorFromEditor>c__AnonStorey1.<>m__0 () (at /Users/builduser/buildslave/unity/build/Editor/Mono/Inspector/InspectorElement.cs:477)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)