Cleanup of warnings in the extensions project

[maririos]

While working on removing AZC0001 we noticed that a bug got introduced on https://github.com/Azure/azure-sdk-for-net/blob/main/sdk/extensions/Azure.Extensions.AspNetCore.DataProtection.Blobs/src/AzureStorageBlobDataProtectionBuilderExtensions.cs#L16 where all the warnings actually got disabled by mistake.

The objective of this issue is to resolve all the warnings and remove #pragma warning disable.

[github-actions]

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