Allow nested arrays for IN queries

[thebrianchen]

Also making another IN filters integration test run against prod.

[mikelehen]

This works in JS but is a little fragile (relies on string equality of magic vales) and won't be portable to other platforms since they don't have access to the methodName. [The only reason we have the methodName in JS is because we try to include it in the error message since (historically at least) in some cases you may not have a meaningful callstack to show you what method the error came from.]

I think it'd probably be better to use context.dataSource which is a more formalized way to know where the data came from and how we should parse it. We could probably get away with context.dataSource !== UserDataSource.Argument here. This means we will disable the nested-array validation in more cases, but I think it's probably okay. If we want to keep it more targeted, we could introduce UserDataSource.ArrayArgument, indicating that we're parsing an array and so "nested" arrays is okay.

The other option I had mentioned previously would be to just parse the elements of the array individually for 'in' filters, e.g. here we would do:

        fieldValue = new ArrayValue((value as unknown[]).map(val => this.firestore._dataConverter.parseQueryValue('Query.where', value)));

I don't have strong feelings, so whichever of these sounds good to you works for me.

[thebrianchen]

I realized that we can't use the context.dataSource !== UserDataSource.Argument check since calling doc.set({ x: FieldValue.arrayUnion(1, ['nested']) }) results in a timeout (didn't dig too deep).

I tried naming, but I'm not sure if allowArrays captures the essence of what we're going for here.

[mikelehen]

This approach looks good, but I'm nitting you some new comments. 😛