[BUG] Onboarding: "City and state" field is limited to US locations and displays "No locations found" during API load.

[RanitManik]

Description

On the Mozilla Monitor new user welcome page (https://monitor.mozilla.org/user/welcome), during the "Enter info" step, the "City and state*" field has two distinct issues that create a poor user experience for non-US users and a confusing UI state.

1. Location Limitation: The "City and state*" field is mandatory, but the available options are limited to cities and states within the United States. This prevents users from outside the US from completing this step accurately.

2. API Loading State: While the locations API is loading, the input field incorrectly displays a "No locations found" message. This is misleading, as it should indicate a loading or pending state.

Steps to Reproduce

1. Navigate to https://monitor.mozilla.org/user/welcome in any web browser.
2. Proceed to the "Enter info" step of the onboarding process.
3. Attempt to enter a city and state outside of the United States in the "City and state*" field.
4. Observe that the autocomplete suggestions are limited to US locations only.
5. Also, note that as the location data is being fetched, the field immediately shows "No locations found" rather than a loading indicator.

Expected Behavior

1. The "City and state*" field should either be optional or should support international locations, allowing users from all regions to enter their correct information.
2. While the locations are loading, the UI should display a loading indicator (e.g., a spinner or a "Loading..." message) to inform the user that data is being fetched.

Actual Behavior

1. The "City and state*" field is mandatory and only accepts US-based locations, effectively blocking non-US users from proceeding with accurate information.
2. The field shows a "No locations found" message during the initial loading of location data, which is confusing and suggests an error rather than a transient state.

Screenshot of the issue