fix: fix storybook coverage task (#5256)

- Fixes storybook coverage command: the coverage directory path was
incorrect, but instead of failing `storybook:test --configuration=ci`,
it was hanging indefinitely.
- Switches back to `concurrently` to launch `storybook:static` and
`storybook:test` in parallel, which allows to use options to explicitly
kill `storybook:static` when `storybook:test` fails.
- Moves `storybook:test --configuration=ci` to its own command
`storybook:static:test`: used in the CI, and can be used locally to run
storybook tests without having to launch `storybook:dev` first.
- Creates command `storybook:coverage` and enables cache for this
command.
- Fixes Jest tests that were failing.
- Improves caching conditions for some tasks (for instance, no need to
invalidate Jest test cache if only Storybook story files were modified).

.github/workflows/actions/task-cache/action.yaml

@@ -24,6 +24,8 @@ runs:
         path: |
           .cache
           .nx/cache
+          node_modules/.cache
+          packages/*/node_modules/.cache
         key: tasks-cache-${{ github.ref_name }}-${{ inputs.tag }}-${{ steps.tasks-key.outputs.key }}${{ inputs.suffix }}-${{ github.sha }}
         restore-keys: |
           tasks-cache-${{ github.ref_name }}-${{ inputs.tag }}-${{ steps.tasks-key.outputs.key }}${{ inputs.suffix }}-