Constructor selection strategy in `GetConstructorAndParameters` diverges from `ActivatorUtilities`

[AGiorgetti]

Description

GetConstructorAndParameters in ServiceCollectionExtensions.KeyedService.cs always selects the constructor with the most parameters:

ctor = target.GetConstructors()
    .OrderByDescending(c => c.GetParameters().Length)
    .First();

This does not match ActivatorUtilities.CreateInstance semantics, which considers which constructor can be best satisfied by the available services. If a type has a constructor with more parameters but not all are resolvable, this will silently select the wrong constructor and fail at runtime.

Suggestion

Consider either:

1. Aligning the behavior with ActivatorUtilities (use ActivatorUtilities.CreateFactory or similar)
2. Adding prominent XML documentation warning about this divergence
3. Validating that all constructor parameters can be satisfied by the dependsOn array + registered services

The existing comment acknowledges this: // maybe we should use the same strategy of: ActivatorUtilities.CreateInstance