Remove deprecated argTypesRegex from Storybook config

Removes the deprecated `actions: { argTypesRegex: "^on[A-Z].*" }` configuration
from the Storybook preview config. This was causing a deprecation warning with
Storybook 10 and the visual test addon.

Since none of our stories currently use action props (onClick, onChange, etc.),
we can safely remove this configuration. If action handlers are needed in the
future, they should be added explicitly using the `fn` function from
`@storybook/test`.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: e-gineer

ui/dashboard/.storybook/preview.jsx

@@ -76,7 +76,6 @@ export const decorators = [
 ];
 
 export const parameters = {
-  actions: { argTypesRegex: "^on[A-Z].*" },
   darkMode: {
     // Override the default dark theme
     dark: {