Decrypting protected settings use hardcoded filename for storage.

Hi,

While looking through the code to decrypt the protectedSettings from the ExtensionConfig, I found the filename "/tmp/kk" is used to store the decoded base64 protectedSettings.

I suggest to use tempfile.TemporaryFile to create a tempfile to be used.

Lines can be viewed here:

[Utils/HandlerUtil.py#L130-L133](https://github.com/Azure/azure-linux-extensions/blob/965923b28a5e7b8f669849d5f2b63489c3275a3f/Utils/HandlerUtil.py#L130-L133)

It will take me some time to make a PR request, as I have other priorities at the moment.

Start in Utils/HandlerUtil.py at lines 130-133 and trace how protectedSettings are decoded and stored. Replace the hardcoded /tmp/kk storage with a temporary-file approach, then verify that decryption still reads the decoded settings and leaves no fixed filename in use.

Written by the indexing model from the issue text.