Retry bundle generation a couple times to hopefully reduce CI instability

[baronfel]

We get the following callstack on several of our single-file publishing tests:

Microsoft.NET.Publish.targets(1132,5): error MSB4018: The "GenerateBundle" task failed unexpectedly. 
Microsoft.NET.Publish.targets(1132,5): error MSB4018: System.IO.IOException: The process cannot access the file '/private/tmp/helix/working/B98A09DE/t/dotnetSdkTests.lUYZADv9/It_can_disabl---A27CFE0E/CetCompat/obj/Debug/net10.0/win-x64/singlefilehost.exe' because it is being used by another process. 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.Win32.SafeHandles.SafeFileHandle.Init(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize, Int64& fileLength, UnixFileMode& filePermissions) 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize, UnixFileMode openPermissions, Int64& fileLength, UnixFileMode& filePermissions, Boolean failForSymlink, Boolean& wasSymlink, Func`4 createOpenException) 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at System.IO.Strategies.OSFileStreamStrategy..ctor(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize, Nullable`1 unixCreateMode) 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at System.IO.File.OpenRead(String path) 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.NET.HostModel.Bundle.Bundler.GenerateBundle(IReadOnlyList`1 fileSpecs) 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.NET.Build.Tasks.GenerateBundle.ExecuteCore() in /_/src/Tasks/Microsoft.NET.Build.Tasks/GenerateBundle.cs:line 81 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.NET.Build.Tasks.TaskBase.Execute() in /_/src/Tasks/Common/TaskBase.cs:line 36 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Execute() 
Microsoft.NET.Publish.targets(1132,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(TaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask)

we think this could be defender, so we want to put a bit of jitter and retry around this Task to see if that smooths things out.