This PR includes the following PRs with no other changes:
- #2466
- #2496
- #2505

It is the collection of all of the work required to update the VC APIs
and fetch the virtual currencies from the new v1 endpoint. To keep the
PR sizes manageable, the work was broken up into smaller PRs, which have
been individually approved and aggregated into this branch.

Forgoing a review on this PR since all changes have already been
reviewed, and we'll do a final review when we merge
`virtual-currency-dev` into `main`

### Description
Android counterpart to
RevenueCat/purchases-ios#5108.

This PR introduces virtual currencies to the Android SDK. It's a large
PR, but all parts of it have been reviewed individually before here:
- #2466
- #2496
- #2505

It includes the following:

### New APIs for Fetching Virtual Currency Balances + Metadata
#### New Top-Level Functions
These functions allow you to fetch the virtual currencies for the
current subscriber. The `invalidateVirtualCurrenciesCache` function
allows developers to clear the cached virtual currencies, which will
then force the refreshing of the virtual currencies from the backend the
next time `getVirtualCurrencies()` is called.

```kotlin
class Purchases {
   fun getVirtualCurrencies(
        callback: GetVirtualCurrenciesCallback,
    )

   fun invalidateVirtualCurrenciesCache()

   val cachedVirtualCurrencies: VirtualCurrencies?
}
```



#### New Objects
```kotlin
class VirtualCurrencies internal constructor(
    val all: Map<String, VirtualCurrency>,
) : Parcelable {
    operator fun get(code: String): VirtualCurrency? = all[code]
}

class VirtualCurrency internal constructor(
    val balance: Int,
    val name: String,
    val code: String,
    val serverDescription: String? = null,
)
```

#### Example Usage
Kotlin:
```swift
Purchases.sharedInstance.invalidateVirtualCurrenciesCache()

Purchases.sharedInstance.getVirtualCurrencies(
    object: GetVirtualCurrenciesCallback {
        override fun onReceived(virtualCurrencies: VirtualCurrencies) {}
        override fun onError(error: PurchasesError) {}
    }
)

Purchases.sharedInstance.getVirtualCurrenciesWith(
        onError = { _: PurchasesError -> },
        onSuccess = { _: VirtualCurrencies -> },
)

val getVirtualCurrenciesResult: VirtualCurrencies = Purchases.sharedInstance.awaitGetVirtualCurrencies()

val cachedVirtualCurrencies = Purchases.sharedInstance.cachedVirtualCurrencies
```

Android counterpart to
RevenueCat/purchases-ios#5108.

This PR introduces virtual currencies to the Android SDK. It's a large
PR, but all parts of it have been reviewed individually before here:
- #2466
- #2496
- #2505

It includes the following:

These functions allow you to fetch the virtual currencies for the
current subscriber. The `invalidateVirtualCurrenciesCache` function
allows developers to clear the cached virtual currencies, which will
then force the refreshing of the virtual currencies from the backend the
next time `getVirtualCurrencies()` is called.

```kotlin
class Purchases {
   fun getVirtualCurrencies(
        callback: GetVirtualCurrenciesCallback,
    )

   fun invalidateVirtualCurrenciesCache()

   val cachedVirtualCurrencies: VirtualCurrencies?
}
```

```kotlin
class VirtualCurrencies internal constructor(
    val all: Map<String, VirtualCurrency>,
) : Parcelable {
    operator fun get(code: String): VirtualCurrency? = all[code]
}

class VirtualCurrency internal constructor(
    val balance: Int,
    val name: String,
    val code: String,
    val serverDescription: String? = null,
)
```

Kotlin:
```swift
Purchases.sharedInstance.invalidateVirtualCurrenciesCache()

Purchases.sharedInstance.getVirtualCurrencies(
    object: GetVirtualCurrenciesCallback {
        override fun onReceived(virtualCurrencies: VirtualCurrencies) {}
        override fun onError(error: PurchasesError) {}
    }
)

Purchases.sharedInstance.getVirtualCurrenciesWith(
        onError = { _: PurchasesError -> },
        onSuccess = { _: VirtualCurrencies -> },
)

val getVirtualCurrenciesResult: VirtualCurrencies = Purchases.sharedInstance.awaitGetVirtualCurrencies()

val cachedVirtualCurrencies = Purchases.sharedInstance.cachedVirtualCurrencies
```