[Static Web Assets] Remove weak ETag generation for compressed assets

[Copilot]

This PR fixes an issue where compressed static web assets were receiving both strong and weak ETags on the same HTTP response, which causes problems in some situations.

Problem

The ApplyCompressionNegotiation task was adding weak ETags (e.g., W/"original-etag") to compressed assets in addition to their own strong ETags (e.g., "compressed-gzip-etag"). This resulted in responses with multiple ETags:

ETag: "sha256-compressed-content-hash"
ETag: W/"sha256-original-content-hash"

Having both strong and weak ETags on the same response can cause issues with HTTP caching and conditional requests in certain scenarios.

Solution

• Removed the code in ApplyCompressionNegotiation.cs (lines 374-389) that was generating weak ETags from the original asset's ETag
• Updated unit tests to no longer expect weak ETags in response headers
• Updated integration tests to remove assertions for weak ETags

Result

Compressed assets now have only their own strong ETag based on the compressed content:

ETag: "sha256-compressed-content-hash"

This eliminates the problematic dual ETag scenario while preserving all caching functionality. The strong ETag from the compressed content is sufficient for proper HTTP cache validation.

Files Changed

• src/StaticWebAssetsSdk/Tasks/ApplyCompressionNegotiation.cs - Removed weak ETag generation logic
• test/Microsoft.NET.Sdk.StaticWebAssets.Tests/StaticWebAssets/ApplyCompressionNegotiationTest.cs - Updated test expectations
• test/Microsoft.NET.Sdk.StaticWebAssets.Tests/StaticWebAssetsCompressionIntegrationTest.cs - Removed weak ETag assertions

Fixes #50290.

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[javiercn]

Undo changes to this file.

[Copilot]

Pull Request Overview

This PR removes the generation of weak ETags for compressed static web assets to eliminate problematic dual ETag responses. Previously, compressed assets received both their own strong ETag and a weak ETag derived from the original asset, which could cause HTTP caching issues.

• Removes weak ETag generation logic from the compression negotiation task
• Updates test expectations across unit and integration tests to match the new behavior
• Preserves strong ETags based on compressed content for proper cache validation

Reviewed Changes

Copilot reviewed 11 out of 73 changed files in this pull request and generated no comments.

File	Description
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_Build_Hosted_Works.Build.staticwebassets.json	Removes duplicate ETag entries from compressed asset baseline test file
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_BuildMinimal_Works.Build.staticwebassets.json	Removes duplicate ETag entries from minimal build baseline test file
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/StaticWebAssets_BackCompatibilityPublish_Hosted_Works.Publish.staticwebassets.json	Removes duplicate ETag entries from back compatibility publish baseline test file
test/Microsoft.NET.Sdk.BlazorWebAssembly.Tests/StaticWebAssetsBaselines/Publish_DoesNotGenerateManifestJson_IncludesJSModulesOnBlazorBootJsonManifest.Publish.staticwebassets.json	Removes duplicate ETag entries from publish baseline test file

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