Add basic Glimmer component definition detection to is-component-definition

Author: andrewpye

addon/helpers/is-component-definition.js

@@ -7,10 +7,23 @@ export function isComponentDefinition(content) {
     return false;
   }
 
+  // Glimmer now uses Symbol keys in its component definitions so we check those first.
+  let symbolPropKeys = Object.getOwnPropertySymbols?.(content);
+  if (symbolPropKeys?.length) {
+    let isGlimmerComponentDefinition = symbolPropKeys.some((symbolPropKey) => {
+      let propValue = content[symbolPropKey];
+      return (
+        propValue &&
+        Object.keys(propValue).some((key) => key === 'ComponentClass')
+      );
+    });
+
+    if (isGlimmerComponentDefinition) {
+      return true;
+    }
+  }
+
   let contentPropNames = Object.keys(content);
-  // This stopped working in Ember 3.17 when it was switched to use a Symbol instead
-  // See https://github.com/glimmerjs/glimmer-vm/blob/master/CHANGELOG.md#v0450-2019-12-18 and
-  // https://github.com/glimmerjs/glimmer-vm/pull/993 for more
   let isPreOctaneComponentDefinition = contentPropNames.some(
     (propName) => propName.indexOf('COMPONENT DEFINITION') > -1
   );