[release/8.0-staging] Do not allow a non-keyed service to be injected to a keyed parameter

[github-actions]

Backport of #105839 to release/8.0-staging plus a new feature switch for any compat issues.

See issue #102204.

/cc @steveharter

Customer Impact

• Customer reported
• Found internally

A customer found unexpected behavior where a keyed service is injected when instead an exception should be thrown.

Regression

• Yes
• No

Testing

The tests from version 9 were ported here; also a compat feature switch was added called "Microsoft.Extensions.DependencyInjection.AllowNonKeyedServiceInject" that when set to true will allow the old behavior in case a customer depends on it. That feature switch does not exist in v9.0.

Risk

Low. This is considered a breaking change since we now throw an exception; normally we don't add breaking changes in a service fix. However, consider:

• Behavior is being corrected which due to the exception, may cause some customer applications to fail which in turn signifies a bug in their code. i.e. customers will now be made aware of any bugs\misuse here.
• Any dependencies on this should be edge case and super rare. However, there is a feature switch added in this PR to keep the old behavior in v8.0.
• For some customers, it is difficult to have well-defined, consistent behavior across v8 and v9 without this fix. Without this fix being ported to v8.0, this code for example would need to be reverted so they can work with the old behavior in v8.

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