fix duplicate importmap (#23282)

examples/webgl_materials_instance_uniform_nodes.html

@@ -11,13 +11,6 @@
 			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl material instance uniform
 		</div>
 
-		<script type="importmap">
-		{
-			"imports": {
-				"three": "../build/three.module.js"
-			}
-		}
-		</script>
 		<!-- Import maps polyfill -->
 		<!-- Remove this when import maps will be widely supported -->
 		<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>

examples/webgl_materials_standard_nodes.html

@@ -13,13 +13,6 @@
 			<a href="http://www.polycount.com/forum/showthread.php?t=130641" target="_blank" rel="noopener">Cerberus(FFVII Gun) model</a> by Andrew Maximov.
 		</div>
 
-		<script type="importmap">
-		{
-			"imports": {
-				"three": "../build/three.module.js"
-			}
-		}
-		</script>
 		<!-- Import maps polyfill -->
 		<!-- Remove this when import maps will be widely supported -->
 		<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>

examples/webgl_points_nodes.html

@@ -12,13 +12,6 @@
 			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> - webgl node particles example
 		</div>
 
-		<script type="importmap">
-		{
-			"imports": {
-				"three": "../build/three.module.js"
-			}
-		}
-		</script>
 		<!-- Import maps polyfill -->
 		<!-- Remove this when import maps will be widely supported -->
 		<script async src="https://unpkg.com/[email protected]/dist/es-module-shims.js"></script>