Fix ChainedConfigurationProvider.Load() to propagate reload to inner IConfigurationRoot

[Copilot]

ChainedConfigurationProvider.Load() was a no-op, so calling IConfigurationRoot.Reload() on a chained configuration never reloaded the inner root's providers — values stayed stale after an explicit reload.

Description

• ChainedConfigurationProvider.Load(): now calls Reload() on the inner configuration when it implements IConfigurationRoot; remains a no-op for plain IConfiguration wrappers.
• Test: ChainedConfiguration_ReloadPropagatestoInnerConfigurationRoot — verifies that a value produced by an inner provider changes after outerConfig.Reload().

var innerConfig = new ConfigurationBuilder()
    .Add(new RandomConfigurationSource())   // generates a new GUID on each Load()
    .Build();

var outerConfig = new ConfigurationBuilder()
    .AddConfiguration(innerConfig)
    .Build();

var before = outerConfig["Random"];
outerConfig.Reload();
var after = outerConfig["Random"];
// before == after  ← was the bug; now before != after

Side-effect to be aware of: an explicit Reload() on the outer root fires its change token twice — once when the inner reload propagates up through the already-registered ChangeToken.OnChange listener, and once from the outer Reload()'s own RaiseChanged(). This is consistent with how automatic (file-watcher) reloads already propagate through chains and is not a data-correctness issue.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• pe4vsblobprodcus351.vsblob.vsassets.io
  • Triggering command: /home/REDACTED/work/runtime/runtime/.dotnet/dotnet dotnet build (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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