Provide a `flushIntervalInSeconds` parameter initialization and configuration of the `AWSCloudWatchLoggingPlugin`.

```swift
do {
    let loggingConfiguration = AWSCloudWatchLoggingPluginConfiguration(logGroupName: "<log-group-name>", region: "<region>", flushIntervalInSeconds: 120)
    let loggingPlugin = AWSCloudWatchLoggingPlugin(loggingPluginConfiguration: loggingConfiguration)
    try Amplify.add(plugin: loggingPlugin)
    try Amplify.configure()
} catch {
    assert(false, "Error initializing Amplify: \(error)")
}
```
