fix(android): fix invalid encoding of scopes in query parameters

[stnguyen90]

What does this PR do?

Before this, the it.value.toString() caused the list of scopes to be encoded like scopes[]=[scope1, scope2] which is invalid.

This change fixes the encoding to scopes[]=scope1&scopes[]=scope2 as expected by the server.

Test Plan

Tested running this code:

fun main() {
    val apiParams = mutableMapOf<String, Any?>(
        "scopes" to listOf("user.read", "user.write"),
    )
    val apiQuery = mutableListOf<String>()
    apiParams.forEach {
        when (it.value) {
            null -> {
                return@forEach
            }
            is List<*> -> { 
                (it.value as List<*>).forEach { v ->
                    apiQuery.add("${it.key}[]=${v.toString()}")
                }
            }
            else -> {
               apiQuery.add("${it.key}=${it.value.toString()}")
            }
        }
    }

    print(apiQuery)
}

in Kotlin playground:

Related PRs and Issues

• 🐛 Bug Report: Invalid scopes when creating OAuth2 session sdk-for-android#60

Have you read the Contributing Guidelines on issues?

Yes