Better errors for Blazor asset integrity problems

[Copilot]

When Blazor asset integrity checks fail (e.g., files modified after publish), users see the cryptic AggregateException_ctor_DefaultMessage resource key instead of a meaningful error.

Description

• ResourceCollectionProvider.LoadResourceCollection(): Wraps JS interop calls in a try-catch. On failure, throws InvalidOperationException with a message identifying the URL and calling out file integrity mismatch as the likely cause:

  Failed to load the Blazor resource collection from '/_framework/resource-collection.abc123.js'.
  This is likely caused by a mismatch in the file integrity check, which can happen when files
  are modified after they are published. Ensure that all published files are deployed correctly
  and that none have been modified after publish.
  

• HostedServiceExecutor.StopAsync(): new AggregateException(exceptions) had no message, causing the .NET resource key AggregateException_ctor_DefaultMessage to surface directly in trimmed WASM apps. Added "One or more hosted services failed to stop." as the explicit message.

• Tests added for both changes (ResourceCollectionProviderTest, HostedServiceExecutorTest).

Original prompt

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This section details on the original issue you should resolve

<issue_title>Better errors for Blazor asset integrity problems</issue_title>
<issue_description>### Is there an existing issue for this?

• I have searched the existing issues

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

See the report in #64923

The problem was due to a failed integrity check for changed file after publish. However, the error the user sees is a very non-descriptive AggregateException_ctor_DefaultMessage.

Describe the solution you'd like

The user should see an error explaining the actual reason.

Additional context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Better errors for Blazor asset integrity problems #65612

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