fix(workflow): show account select in Send Email node when no account is connected (#23066)

# Why

In the workflow **Send Email** (and Draft Email) node, when the
workspace has no eligible connected account, the **Account** field
disappears entirely — only the variable picker icon remains. The "Add
account" call-to-action is unreachable, so there is no way to connect an
account from the node.

## Root cause

Regression from #21075. `FormSelectFieldInput` used to always pass a
default empty option ("No Account") to `<Select>`; since #21075 it only
prepends it when `isNullable` is set, and the email account field
doesn't set it. With zero connected accounts, `<Select>` then has no
option to resolve a selected option from and bails out rendering an
empty fragment — even though a `callToActionButton` is configured:

```tsx
// Select.tsx
if (!isDefined(controlSelectedOption)) {
  return <></>;
}
```

# What changed

`FormSelectFieldInput` now prepends the empty option whenever the field
is nullable **or there are no options at all**. A populated non-nullable
select still offers no clearing choice (the #21075 behavior is
preserved); an empty one renders its "No X" state so the control — and
its call-to-action — stay visible and clickable.

# Test plan

- New story `FormSelectFieldInput > NoOptionsWithCallToAction`: zero
options + CTA renders the "No Work Policy" control, the dropdown opens,
and the CTA is clickable.
- New story `WorkflowEditActionEmailBase > NoConnectedAccounts`: with
`MyConnectedAccounts` mocked to `[]`, the Account field renders "No
Account" instead of vanishing. The meta's msw handlers move to the
keyed-object form so the story can override a single query (story-level
handler arrays get concatenated after the meta's, and msw's first match
wins), and the story evicts the module-singleton Apollo client's cached
accounts so it actually hits the empty mock.
- `npx nx typecheck twenty-front` and `npx nx lint:diff-with-main
twenty-front` pass; both story files pass under the storybook vitest
project (13 stories total).

<!-- This is an auto-generated description by cubic. -->
<a
href="https://cubic.dev/pr/twentyhq/twenty/pull/23066?utm_source=github"
target="_blank" rel="noopener noreferrer"
data-no-image-dialog="true"><picture><source
media="(prefers-color-scheme: dark)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"><source
media="(prefers-color-scheme: light)"
srcset="https://www.cubic.dev/buttons/review-in-cubic-light.svg"><img
alt="Review in cubic"
src="https://www.cubic.dev/buttons/review-in-cubic-dark.svg"></picture></a>
<!-- End of auto-generated description by cubic. -->

packages/twenty-front/src/modules/object-record/record-field/ui/form-types/components/FormSelectFieldInput.tsx

@@ -102,9 +102,8 @@ export const FormSelectFieldInput = ({
     Icon: IconCircleOff,
   };
 
-  const optionsWithEmptyOption = isNullable
-    ? [emptyOption, ...options]
-    : options;
+  const optionsWithEmptyOption =
+    isNullable || options.length === 0 ? [emptyOption, ...options] : options;
 
   const selectedOption = optionsWithEmptyOption.find(
     (option) => option.value === draftValue.value,

packages/twenty-front/src/modules/object-record/record-field/ui/form-types/components/__stories__/FormSelectFieldInput.stories.tsx

@@ -126,6 +126,37 @@ export const NonNullable: Story = {
   },
 };
 
+export const NoOptionsWithCallToAction: Story = {
+  args: {
+    label: 'Work Policy',
+    defaultValue: undefined,
+    options: [],
+    onChange: fn(),
+    callToActionButton: {
+      text: 'Add work policy',
+      onClick: fn(),
+    },
+  },
+  play: async ({ args, canvasElement }) => {
+    const canvas = within(canvasElement);
+
+    const selectControl = await canvas.findByText('No Work Policy');
+    expect(selectControl).toBeVisible();
+
+    await userEvent.click(selectControl);
+
+    const dropdown = within(canvasElement.ownerDocument.body);
+
+    await waitFor(() => {
+      expect(dropdown.getByText('Add work policy')).toBeVisible();
+    });
+
+    await userEvent.click(dropdown.getByText('Add work policy'));
+
+    expect(args.callToActionButton?.onClick).toHaveBeenCalled();
+  },
+};
+
 export const WithVariablePicker: Story = {
   args: {
     label: 'Work Policy',