Resetting material shader throw errors when material shader under TextMesh pro is set to TextmeshPro/Distance field (Surface).

Steps to Repro:
1. Create a new project.
2. GameObject -> 3D Object -> Text Mesh Pro - Text.
3. Import Essential Resources and Example & Extras.
4. Select Text Mesh Pro - Text in the hierarchy.
5. Set material shader to TextmeshPro/Distance field (Surface)
6. Reset shader material through cogwheel.

Actual Result:
"Material doesn't have a float or range property '_Stencil'" error thrown.

Expected Result:
Material shader properties reset.

Environment:
Windows & Mac

Reproducible on:
2019.2.0a3, 2019.1.0b1, 2018.1.0b5

Note: TextMeshPro introduced in 2018.1.0b5

Stack Trace:
1. Material doesn't have a float or range property '_Stencil'
UnityEngine.Material:GetFloat(Int32)
TMPro.EditorUtilities.TMP_ContextMenus:ResetSettings(MenuCommand) (at Library/PackageCache/com.unity.textmeshpro@1.3.0/Scripts/Editor/TMPro_ContextMenus.cs:179)

2. Material doesn't have a float or range property '_StencilComp'
UnityEngine.Material:GetFloat(Int32)
TMPro.EditorUtilities.TMP_ContextMenus:ResetSettings(MenuCommand) (at Library/PackageCache/com.unity.textmeshpro@1.3.0/Scripts/Editor/TMPro_ContextMenus.cs:180)