fix a handful of strict null errors; make test config also be strict

These errors only arose because I didn't run `npm build`, only `npm
test`. Then, when I tried building the null checks failed. Keeping the
two config fiels in sync will help prevent this issue in the future

ts/docx/table/grid.ts

@@ -14,6 +14,8 @@ class GridColAttributes extends XmlAttributeComponent<{w: number}> {
 export class GridCol extends XmlComponent {
     constructor(width?: number) {
         super("w:gridCol");
-        this.root.push(new GridColAttributes({w: width}));
+        if (width !== undefined) {
+            this.root.push(new GridColAttributes({w: width}));
+        }
     }
 }