Setting `timezone="UTC"` for `TimePickerElement` should display "UTC" as the "hint" text, not "Monrovia, Reykjavik"

I am trying to build a form for users to fill out, and it includes a time picker. I want to "force" users to use UTC for this time picker. However, when I set timezone="UTC", the label that is provided is "Monrovia, Reykjavik". This is causing a bunch of downstream confusion that I basically have no control over the representation of.

I could imagine two solutions to this:

• If I supply "UTC" as the timezone, it should just show "Time zone: UTC" as the "hint" under the form field.
• The TimePickerElement should allow users to specify its own hint, so that I can display whatever I want, as the builder of the form.

Category (place an x in each of the [ ])

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.models (UI component builders)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.scim (SCIM API client)
• slack_sdk.rtm (RTM client)
• slack_sdk.signature (Request Signature Verifier)

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

Start at the TimePickerElement entry point in the slack_sdk.models UI component builders and trace how its timezone value becomes the hint text. Confirm the intended resolution with maintainers, then make the displayed hint represent UTC clearly or support a caller-provided hint, and verify the resulting form-field behavior.