fix case when a.auditProperty is undefined

Author: paulirish

src/utils/annotations.js

@@ -27,9 +27,8 @@ exports.setFailedAnnotations = async function setFailedAnnotations(resultsPath)
     const assertionsText = assertions.map(a => {
       const emoji = a.level === 'error' ? '❌' : '⚠️'
       return (
-        `${emoji} \`${a.auditId}.${a.auditProperty}\` ${a.level === 'error' ? 'failure' : 'warning'} for \`${
-          a.name
-        }\` assertion` +
+        `${emoji} \`${a.auditId}${a.auditProperty ? '.' + a.auditProperty : ''}\` `+
+        `${a.level === 'error' ? 'failure' : 'warning'} for \`${a.name}\` assertion` +
         `${a.auditTitle ? ` (${a.auditTitle}: ${a.auditDocumentationLink})` : ''}\n` +
         `Expected ${a.operator} ${a.expected}, but found ${a.actual}`
       )