[TimePickerDropdown] Single label for range does not span across element

[davidicus]

What package is this for?

• [X] React
• [ ] Angular

Describe the bug

When the option to hide secondary label is chosen on a range input the primary label is supposed to span across both text input fields. Now there is a max width being applied which is needed when both labels are shown. The fix is to just apply a :not(legend) to the end of the selector applying the max width to the labels.

To Reproduce

Steps to reproduce the behavior:

1. Go to this story
2. Click the hide secondary label knob and choose range from the Type dropdown
3. Make the text in the i18n knob's labelText field a long string
4. See error

Please create a reduced test case in CodeSandbox: https://codesandbox.io/s/github/carbon-design-system/carbon-addons-iot-react/tree/next/packages/react/examples/codesandbox

Expected behavior

When secondary label is hidden the primary label should span the entire element.

Current	Desired