[Xamarin.Android.Build.Tasks] Allow override of uncompressedGlob.

[dellis1972]

Users reported that when they added a custom uncompressedGlob entry to the $(AndroidBundleConfigurationFile), it was ignored. This is because the MergeArrayHandling option we were using in the BuildAppBundle task was set to MergeArrayHandling.Replace.

As a result we would just overwrite the user config with our own. We should be using the MergeArrayHandling.Union option instead. This with merge the arrays , but will remove duplicates. This should allow users to provide additional uncompressedGlob options.

A unit test has been added to test this new behaviour.

[jonathanpeppers]

LGTM, but a lot of CI failed due to a random policy thing.

We'll probably have to rerun when that is fixed.

[dellis1972]

/azp run

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Azure Pipelines successfully started running 1 pipeline(s).

[pjcollins]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jonpryor]

Context: https://www.newtonsoft.com/json/help/html/P_Newtonsoft_Json_Linq_JsonMergeSettings_MergeArrayHandling.htm
Context: https://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_Linq_MergeArrayHandling.htm

The MergeArrayHandling enum has .Concat, .Union, .Replace (what we previously used), and .Merge.

What the docs don't say is what those necessarily mean. .Concat seems simple enough -- concatenate the contents of the latter array to the former -- but how do .Union and .Merge differ from each other?

Merge Merge array items together, matched by index

I don't know what this means.

For example, what happens if we merge */*.mp3 with the default list? https://github.com/xamarin/xamarin-android/blob/e31afeec350db8550fb1073ef1b87f7af6c0d288/src/Xamarin.Android.Build.Tasks/Tasks/BuildAppBundle.cs#L22-L60

*/*.mp3 isn't identical to **/*.mp3, so…what would happen? Which comes first? Does that matter?

Is .Union the right value here?

[jonpryor]

@dellis1972: please rebase this PR; the unit test failures are "weird", and I don't see how this PR could cause them.

[dellis1972]

Merge Merge array items together, matched by index

I'm not sure what this means either. I suspect it means by index into the array ... so item 3 in the source array will be overwritten by item 3 if the new array (if it exists). That sounds a bit silly to me.