Re-enable 4 validation tests that now pass on Babylon Native

A full `--include-excluded` sweep of validation_native.js on latest master
shows these four previously-quarantined tests now pass on Win32 D3D11. Their
exclusion reasons (Win32 crashes / "disabled until BabylonNative fixes") are
resolved, so this re-enables them. config.json-only change.

- NME Multi Build (was: "Test crashes or hangs on Babylon Native")
- Custom render target (was: "crashes on Win32 D3D11 plain (STATUS_BREAKPOINT)")
- UV2 Morphing (was: "fails on Win32 D3D11 sweep; disabled until BabylonNative fixes")
- Vertex Pulling - Morph Targets and Bones (same)

Each verified passing 3x in isolation and in the normal (non-excluded) run flow.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bkaradzic-microsoft

Apps/Playground/Scripts/config.json

@@ -843,8 +843,6 @@
         {
             "title": "NME Multi Build",
             "playgroundId": "#D8AK3Z#113",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes or hangs on Babylon Native",
             "referenceImage": "nme-multi-build.png"
         },
         {
@@ -1265,8 +1263,6 @@
         {
             "title": "Custom render target",
             "playgroundId": "#TQCEBF#5",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Test crashes on Win32 D3D11 plain (STATUS_BREAKPOINT)",
             "referenceImage": "customRTT.png"
         },
         {
@@ -2839,9 +2835,7 @@
         {
             "title": "UV2 Morphing",
             "playgroundId": "#N5DLM7#1",
-            "referenceImage": "UV2-Morphing.png",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "referenceImage": "UV2-Morphing.png"
         },
         {
             "title": "FrameGraph nrge shadows",
@@ -4449,9 +4443,7 @@
         {
             "title": "Vertex Pulling - Morph Targets and Bones",
             "playgroundId": "#CT4C3C#2",
-            "referenceImage": "vertexPullingMorphBones.png",
-            "excludeFromAutomaticTesting": true,
-            "reason": "Test fails locally on Win32 D3D11 sweep; disabled until BabylonNative fixes are made."
+            "referenceImage": "vertexPullingMorphBones.png"
         },
         {
             "title": "Vertex Pulling - isUnIndexed with index buffer",