Update Storybook to 7.6.13 (#1812)

# Pull Request

## 🤨 Rationale

Wanted to see if there were any improvements.

## 👩‍💻 Implementation

- Bumped version from 7.4.0 to 7.6.13
- Had to work around an
[issue](storybookjs/storybook#25170) related
to the typing of `withActions` decorator of actions add-on.
~~Re-exporting `withActions` from our Storybook utilities file with a
type that works (based on [comment in related
issue](storybookjs/storybook#22384 (comment)
Now providing type argument to generic `withActions` function.
- Marked docs support disabled in `addon-essentials` since we import
that addon separately (`addon-docs`) so we can configure it. Not sure if
this improves anything, but it doesn't seem to hurt.
- Also fixes #1639

## 🧪 Testing

Ran Storybook. `npm run storybook` seems to get everything ready about
25% faster (40s -> 30s).

## ✅ Checklist

<!--- Review the list and put an x in the boxes that apply or ~~strike
through~~ around items that don't (along with an explanation). -->

- [x] I have updated the project documentation to reflect my changes or
determined no changes are needed.

change/@ni-nimble-components-6e7cd0d9-ed67-48d4-b27c-037fc49f4d5e.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Update Storybook to 7.6.13",
+  "packageName": "@ni/nimble-components",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}