Feature flag `useEnabledMfas`'s default value for new projects is wrong

**Describe the content issue**:
In below document, the default value for new projects for feature flag `useEnabledMfas` is marked as false, but in fact it should be true.

**URL page where content issue is**:
https://docs.amplify.aws/javascript/tools/cli/reference/feature-flags/#useEnabledMfas

**Ref.**
https://github.com/aws-amplify/amplify-cli/blob/dev/packages/amplify-cli-core/src/feature-flags/featureFlags.ts#L714
```
{
name: 'useEnabledMfas',
type: 'boolean',
defaultValueForExistingProjects: false,
defaultValueForNewProjects: true,
}
```