Enrich existing Mongo client with telemetry instrumentation

Hi,
Currently, in [Aspire.Npgsql.EntityFrameworkCore.PostgreSQL](https://github.com/dotnet/aspire/blob/main/src/Components/Aspire.Npgsql.EntityFrameworkCore.PostgreSQL) we have the capability of using existing DBContext and just enrich it with telemetry data with [`EnrichNpgsqlDbContext`](https://github.com/dotnet/aspire/blob/main/src/Components/Aspire.Npgsql.EntityFrameworkCore.PostgreSQL/AspireEFPostgreSqlExtensions.cs#L107).

It is very better we have the same flexibility for [Aspire.MongoDB.Driver](https://github.com/dotnet/aspire/blob/main/src/Components/Aspire.MongoDB.Driver) and just add telemetry data with a `EnrichMongoClient` method and using exisitng MongoClient and MongoDatabase.

If it is acceptable, I can create a Pull Request for it.