Feature upgrade: UUI-select does not reflect value

[NguyenThuyLan]

Description

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)

Motivation and context

The uui-select component receives an array of options. If one of the options has selected: true, then that will be the one selected.
That is not intuative, as a developer usually would set the value in this style:

const CountryOptions = [
  { value: "AD", name: "Andorra" },
  { value: "AE", name: "United Arab Emirates" },
  { value: "AL", name: "Albania" },
  { value: "AM", name: "Armenia" },
];

@property()
selectedCountry = "AM";

<uui-select
          label="Select country"
          placeholder="Select country..."
          value=${this.selectedCountry ?? ""}
          .options=${
            CountryOptions
          }
          @change=${this.#onCountryChanged}
        ></uui-select>

This PR is about making above work.

How to test?

Screenshots (if appropriate)

Checklist

• If my change requires a change to the documentation, I have updated the documentation in this pull request.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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[iOvergaard]

I see your point, @LanThuyNguyen, that this is more intuitive. However, it is a breaking change that we cannot get into a minor release if we remove the previous option. So I was wondering if you think we can get both ways to work, and then also deprecate the old option (selected?: boolean) instead of removing it entirely.

What do you think?