Don't try to create tab if windowId is falsey

Fixes brave#8545

Auditors: @mrose17

Test plan:
1. Ensure Payments are enabled and Open `about:blank`
2. From the `Shields` menu, pick `Site Shield Settings...`
3. Verify nothing happens and that the app doesn't crash

app/browser/tabs.js

@@ -618,6 +618,9 @@ const api = {
     const url = normalizeUrl(createProperties.get('url'))
     createProperties = createProperties.set('url', url)
     const windowId = createProperties.get('windowId')
+    if (!windowId) {
+      return state
+    }
     const tabData = tabState.getMatchingTab(state, createProperties, windowId, url)
     if (tabData) {
       const tab = getWebContents(tabData.get('id'))