fix: await useFactory resolution when registering Mikro ORM with forRootAsync

[SteadEXE]

When MikroORM's module is loaded with forRootAsync, it throws an error if useFactory is async or returns a promise :
No driver specified, please fill in the `driver` option or use `defineConfig` helper (to define your ORM config) or `MikroORM` class (to call the `init` method) exported from the driver package (e.g. `import { defineConfig } from '@mikro-orm/mysql'; export defineConfig({ ... })`).

This is understandable because factoryOptions is now a promise instead of the options object itself.

It makes sure that createMikroOrmAsyncOptionsProvider uses the result of the promise instead of the promise itself.

[B4nan]

thanks!