Extra logging dlls should not be loaded when AzureWebJobsDashboard is not set.

This will have an impact on cold start.

Also need to make sure no logger activity writes to storage when it's not expected to.

From email thread:

Just debugging locally, without any dashboard setting, if I put a breakpoint in FunctionInstanceLogCollectorProvider.Create, it will hit and if I step over I see:

'Microsoft.Azure.WebJobs.Script.WebHost.exe' (CoreCLR: clrhost): Loaded 'D:\code\azure-functions-host\src\WebJobs.Script.WebHost\bin\Debug\netcoreapp3.1\Microsoft.Azure.Cosmos.Table.dll'. Skipped loading symbols. Module is optimized and the debugger option 'Just My Code' is enabled.
'Microsoft.Azure.WebJobs.Script.WebHost.exe' (CoreCLR: clrhost): Loaded 'D:\code\azure-functions-host\src\WebJobs.Script.WebHost\bin\Debug\netcoreapp3.1\Microsoft.Azure.WebJobs.Logging.dll'.