Added more information about DOTNET_ENVIRONMENT value and precedence

[ozgey99]

📋 Description

Some customers are overriding the environment value through web.config which means that we don't see the expected runtime environment value set through Umbraco Cloud Portal being retrieved in executed code.
It would be really nice to give a bit more information on the precedence rules.

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I've followed the Umbraco Documentation Style Guide and can confirm that:

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Product & Version (if relevant)

Umbraco Cloud

Deadline (if relevant)

No deadline

📚 Helpful Resources

• 🧾 Umbraco Contribution Guidelines
• ✍️ Umbraco Documentation Style Guide