ADS: Fix selected option in RadioListDialog (#2577)

Task/Issue URL:
https://app.asana.com/0/1202857801505092/1203456015669172/f

### Description

- Selected option was not working for RadioListAlertDialogBuilder
- Disable positive button if no option is selected by default

### UI changes
| Before  | After |
| ------ | ----- |

![Screenshot_20221129-115404_DuckDuckGo](https://user-images.githubusercontent.com/20798495/204546959-54f42f96-fffc-42bc-9821-b39f7d201146.jpg)|![Screenshot_20221129-134905_DuckDuckGo](https://user-images.githubusercontent.com/20798495/204546976-cbda520d-e338-4636-aa99-57b358f89599.jpg)|

![Screenshot_20221129-115404_DuckDuckGo](https://user-images.githubusercontent.com/20798495/204546959-54f42f96-fffc-42bc-9821-b39f7d201146.jpg)|![Screenshot_20221129-143842_DuckDuckGo](https://user-images.githubusercontent.com/20798495/204576904-e45e9893-87c3-4ec3-aeb6-4676d0563261.jpg)|

common-ui/src/main/java/com/duckduckgo/mobile/android/ui/view/dialog/RadioListAlertDialogBuilder.kt

@@ -53,7 +53,7 @@ class RadioListAlertDialogBuilder(val context: Context) : DaxAlertDialog {
         private set
     var optionList: MutableList<CharSequence> = mutableListOf()
         private set
-    var selectedOption = 0
+    var selectedOption: Int? = null
         private set
 
     fun setTitle(@StringRes textId: Int): RadioListAlertDialogBuilder {
@@ -78,7 +78,7 @@ class RadioListAlertDialogBuilder(val context: Context) : DaxAlertDialog {
 
     fun setOptions(
         @StringRes stackedButtonTextId: List<Int>,
-        selectedItem: Int = 0,
+        selectedItem: Int? = null,
     ): RadioListAlertDialogBuilder {
         stackedButtonTextId.forEach {
             optionList.add(context.getText(it))
@@ -143,18 +143,20 @@ class RadioListAlertDialogBuilder(val context: Context) : DaxAlertDialog {
             binding.radioListDialogMessage.text = messageText
         }
 
-        optionList.forEach {
+        optionList.forEachIndexed { index, option ->
             val radioButton = RadioButton(context, null)
-            radioButton.text = it
+            radioButton.id = index + 1
+            radioButton.text = option
             val params = RadioGroup.LayoutParams(RadioGroup.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.WRAP_CONTENT)
             radioButton.layoutParams = params
             binding.radioListDialogRadioGroup.addView(radioButton)
         }
 
         with(binding.radioListDialogRadioGroup) {
-            check(selectedOption)
-            setOnCheckedChangeListener { group, checkedId ->
+            selectedOption?.let { check(it) }
+            setOnCheckedChangeListener { _, checkedId ->
                 listener.onRadioItemSelected(checkedId)
+                binding.radioListDialogPositiveButton.isEnabled = true
             }
         }
 
@@ -163,6 +165,7 @@ class RadioListAlertDialogBuilder(val context: Context) : DaxAlertDialog {
             listener.onPositiveButtonClicked(binding.radioListDialogRadioGroup.checkedRadioButtonId)
             dialog.dismiss()
         }
+        binding.radioListDialogPositiveButton.isEnabled = selectedOption != null
 
         binding.radioListDialogNegativeButton.text = negativeButtonText
         binding.radioListDialogNegativeButton.setOnClickListener {