Add .NET 10 multi-targeting support

[Copilot]

Fixes #5576

Changes proposed in this request

Added .NET 10 multi-targeting across all MSAL libraries, tests, and dev apps while maintaining .NET 8 compatibility.

• Client libraries (5 projects): Microsoft.Identity.Client (including Android/iOS with net10.0-android and net10.0-ios), Extensions.Msal, MtlsPop, Desktop.WinUI3 now directly target net10.0 alongside net8.0
• Test projects (4 projects): Unit, Integration, E2E, Performance tests updated to target net10.0
• Dev apps (9 projects): NetCoreTestApp, WebApi, CacheExtension, MacConsoleAppWithBroker, TestTelemetry, and Managed Identity apps updated

Projects now use straightforward multi-targeting:

<TargetFrameworks>net8.0;net10.0</TargetFrameworks>

For mobile platforms:

<TargetFrameworkNetAndroid>net8.0-android</TargetFrameworkNetAndroid>
<TargetFrameworkNetIos>net8.0-ios</TargetFrameworkNetIos>
<TargetFrameworkNet10Android>net10.0-android</TargetFrameworkNet10Android>
<TargetFrameworkNet10Ios>net10.0-ios</TargetFrameworkNet10Ios>

All projects now build for both .NET 8 and .NET 10 without conditional logic.

Testing

Verified all modified projects build successfully. No code changes required—only project configuration updates.

Performance impact

None. Configuration-only changes.

Documentation

• All relevant documentation is updated.

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Engineering task] Update MSAL to use Net 10</issue_title>
<issue_description>### Task type

Development

Description

[Engineering task] Update MSAL to use Net 10

Solution

[Engineering task] Update MSAL to use Net 10</issue_description>

<agent_instructions>update product code and tests</agent_instructions>

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

@gladjohn We need to support both net 8 and net 10

• Fixes [Engineering task] Update MSAL to use Net 10 #5576

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[gladjohn]

@copilot We do not need this check. DotNet10SdkAvailable

[Copilot]

Removed the DotNet10SdkAvailable check from Directory.Build.props and all project files. All projects now directly target both net8.0 and net10.0 without conditional logic. (06ed251)

[bgavrilMS]

Why are we doing this @gladjohn ?

[gladjohn]

Why are we doing this @gladjohn ?

an easy way to get net 10 for the httpclient testing Chris and I were doing. This can be closed.