Remove hardcoded exception message on the container set function.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        | no

[DependencyInjection] Replaced hardcoded 'prototype' string with the 'PROTOTYPE' constant on the InvalidArgumentException, when using
the 'set' function on the Container with 'prototype' scope.