Hotfix for metadata potentially being undefined in the SBOM json (#1132)

## Description

Adds an undefined check for metadata to viewer.js


![image](https://user-images.githubusercontent.com/3977569/207736087-105fbfd6-85db-4b8f-a58c-9abcebf38a16.png)

## Related Issue

Fixes #1131

## Type of change

- [X] Bug fix (non-breaking change which fixes an issue)

src/internal/packager/sbom/viewer/viewer.js

@@ -28,9 +28,9 @@ function initData() {
             artifact.name,
             artifact.version,
             fileList(artifact.metadata),
-            artifact.metadata.description || '-',
-            (artifact.metadata.maintainer || '-').replace(/\u003c(.*)\u003e/, '&nbsp;|&nbsp;&nbsp;<a href="mailto:$1">$1</a>'),
-            artifact.metadata.installedSize || '-',
+            (artifact.metadata && artifact.metadata.description) || '-',
+            ((artifact.metadata && artifact.metadata.maintainer) || '-').replace(/\u003c(.*)\u003e/, '&nbsp;|&nbsp;&nbsp;<a href="mailto:$1">$1</a>'),
+            (artifact.metadata && artifact.metadata.installedSize) || '-',
         ];
     });
 
@@ -61,15 +61,17 @@ function initData() {
 }
 
 function fileList(metadata) {
-    const list = (metadata.files || [])
-        .map(file => {
-            return file.path || ''
-        })
-        .filter(test => test)
-
-    if (list.length > 0) {
-        flatList = list.sort().join('<br>');
-        return `<a href="#" onClick="showModal('${metadata.package}','${flatList}')">${list.length} files</a>`
+    if (metadata) {
+        const list = (metadata.files || [])
+            .map(file => {
+                return file.path || ''
+            })
+            .filter(test => test)
+
+        if (list.length > 0) {
+            flatList = list.sort().join('<br>');
+            return `<a href="#" onClick="showModal('${metadata.package}','${flatList}')">${list.length} files</a>`
+        }
     }
 
     return '-';