Use TimezoneDropdown from shared components

What does this MR do and why?

Migrate outdated timezone selector to Vue Compo... (&8530)

There are a couple of outdated dropdowns which are used to select timezones. These can be migrated to the existing timezone_dropdown Vue component.

Exchange custom TimezoneDropdown that is used on the profile page to the shared component

Related to #369973 (closed)

Screenshots or screen recordings

Visual change - padding on top of the Time zone label UPD: change formatting for deploy freeze timezone (+ and a space in front of the prefix)

Before	After

How to set up and validate locally

1. Open the http://localhost:3000/-/profile page
2. Update the TimeZone dropdown and save the form
3. Make sure that the value is properly updated after safe

To check deploy freeze update:

1. Open a project, Settings -> CI/CD -> Deploy freeze
2. Add a new deploy freeze

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.