Picker Attribute "SelectedIndex" Not being respected on page load - fix

[kubaflo]

Fixes #9150
Fixes #22028

For the following code:

        <Picker FontSize="15"
                AutomationId="picker"
                SelectedIndex="1"
                x:Name="picker">
            <Picker.ItemsSource>
                <x:Array Type="{x:Type x:String}">
                    <x:String>0</x:String>
                    <x:String>1</x:String>
                    <x:String>2</x:String>
                </x:Array>
            </Picker.ItemsSource>
        </Picker>

Before	After

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[jsuarezruiz]

@kubaflo Could you rebase to fix the conflicts? Thanks in advance.

[kubaflo]

@jsuarezruiz I've rebased and solved conflicts :)

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[bhavanesh2001]

Can this be reviewed?

[bhavanesh2001]

Couple of things I noticed

• If i define my picker something like this

 <Picker  SelectedIndex="2"
                Title="Choose an item" SelectedIndexChanged="Picker_SelectedIndexChanged" 
                 >
            <Picker.Items>
                <x:String>Item 1</x:String>
                <x:String>Item 2</x:String>
                <x:String>Item 3</x:String>
                <x:String>Item 4</x:String>
                <x:String>Item 5</x:String>
            </Picker.Items>
        </Picker>

this will throw on page load in both iOS and Android

• SelectedIndexChanged is getting fired on Page load in Android but not in iOS . I think it shouldn't get fired .