Expose `NoLaunchProfile` in `DistributedApplicationOptions` to disable using launchProfile.json permanently

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

We use Aspire primarily for integration tests and for running a local environment. Several of our test projects start multiple containers and local projects. When launch profiles are applied, local projects bind to fixed ports, which causes port clashes and cross-tenant bleed when multiple test projects run in parallel.

Sample fixture for XUnit

```csharp
public sealed class ApplicationHostFixture()
: DistributedApplicationFactory(
typeof(MyCompany_AppHost),
[
$"--TENANT={Tenant}",
]
),
IAsyncLifetime
{}

[CollectionDefinition("Integration Tests Collection")]
public abstract class ApplicationHostCollection : ICollectionFixture;
```

Expected behavior:
ports for local projects should be randomized (ephemeral) per test run/project to avoid interference.

### Describe the solution you'd like

First-class support to run without launch profiles

1. Global opt-out of launch profiles
Via environment variable, e.g. `ASPIRE_DISABLE_LAUNCH_PROFILES=true`

Or via DistributedApplicationOptions, e.g.:

```csharp
var builder = DistributedApplication.CreateBuilder(new DistributedApplicationOptions
{
UseLaunchProfiles = false
});
```

2. Per-project opt-out

A fluent API to disable the launch profile for a specific project:
```csharp
_ = builder
.AddProject("mock-grpc")
.NoLaunchProfile()
.WithHttpEndpoint(port: null, targetPort: 5000, name: "http")
.WithHttp2Endpoint()
.AsHttp2Service();
```

3. Ephemeral port assignment

When `.WithHttpEndpoint(port: null, ...)` is used (globally or per project), Aspire should assign a free ephemeral port at runtime and propagate that binding to dependent services and generated connection strings/URIs.

### Additional context

_No response_