Fix browser build

[radekdoulik]

No description provided.

[dotnet-policy-service]

Tagging subscribers to this area: @mangod9
See info in area-owners.md if you want to be subscribed.

[radekdoulik]

Fix build error in https://dev.azure.com/dnceng-public/public/_build/results?buildId=1244620&view=logs&jobId=1236c61a-731e-5ae8-c2ca-7ddc55e20b2e&j=1236c61a-731e-5ae8-c2ca-7ddc55e20b2e&t=836834d0-290a-514a-aa10-6022eb7d1f99

##[error]src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPool.Browser.Threads.cs(13,36): error CS1696: (NETCORE_ENGINEERING_TELEMETRY=Build) Single-line comment or end-of-line expected
/__w/1/s/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPool.Browser.Threads.cs(13,36): error CS1696: Single-line comment or end-of-line expected [/__w/1/s/src/mono/System.Private.CoreLib/System.Private.CoreLib.csproj]
##[error]src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPool.Browser.Threads.cs(14,6): error CS1513: (NETCORE_ENGINEERING_TELEMETRY=Build) } expected
/__w/1/s/src/libraries/System.Private.CoreLib/src/System/Threading/ThreadPool.Browser.Threads.cs(14,6): error CS1513: } expected [/__w/1/s/src/mono/System.Private.CoreLib/System.Private.CoreLib.csproj]

Build FAILED.

[Copilot]

Pull request overview

This PR fixes a syntax error in the browser threading implementation file that would have prevented the browser build from compiling. The file had malformed structure with missing line breaks and a missing closing brace for the namespace.

Key Changes

• Adds proper line break after #pragma warning restore IDE0060
• Adds missing closing brace } for the namespace declaration

[pavelsavara]

/ba-g ci timeouts