Add package attributes to csproj files to meet packaging requirements

[Naiyuan Tian (nytian)]

As titled.

[Copilot]

Pull request overview

This PR updates the repository’s NuGet packaging metadata to comply with current NuGet requirements by switching from deprecated URL-based icon metadata to file-based package assets and centralizing shared packaging settings in DurableTask.props.

Changes:

• Replace deprecated PackageIconUrl usage with PackageIcon and add PackageReadmeFile in the shared props.
• Ensure logo.png and README.md are packed into NuGet packages from a shared location for packable projects.
• Remove NU5048 suppression from props and affected .csproj files after eliminating the deprecated metadata usage.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tools/DurableTask.props	Centralizes package icon/readme metadata and packs shared logo.png + README.md; removes NU5048 from NoWarn.
src/DurableTask.Emulator/DurableTask.Emulator.csproj	Removes NU5048 suppression now that deprecated icon metadata is no longer used.
src/DurableTask.Core/DurableTask.Core.csproj	Removes per-project readme packing/config in favor of shared props; removes NU5048 suppression.
src/DurableTask.AzureStorage/DurableTask.AzureStorage.csproj	Removes per-project readme packing/config in favor of shared props; removes NU5048 suppression.
src/DurableTask.ApplicationInsights/DurableTask.ApplicationInsights.csproj	Removes NU5048 suppression now that deprecated icon metadata is no longer used.

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