chip-tool handling of optional arguments that are not at the end of the list is all broken

[bzbarsky-apple]

Problem

After #11749 the behavior of chip-tool is as follows:

1. Walk argv for indices up to required-arg-count and initialize the arguments at those indices.
2. Walk argv 2 at a time for indices corresponding to the count of optional args and init arguments that match by name.

But what happens if the optional arg is not at the end? A real-life example of this is:

chip-tool otasoftwareupdaterequestor announce-ota-provider ProviderLocation VendorId AnnouncementReason [--MetadataForNode] node-id endpoint-id

but let's walk through a hypothetical example with just two args the first of which is optional: my-command [--optional-arg] required-arg.

As far as I can tell, what this will do is:

1. If called with one argument, initialize the optional arg with that value and leave the required arg uninitialized.
2. If called with three arguments, init the optional arg with the first argument, then try to match the second arg against the string "--required-arg", etc.

Proposed Solution

Either fix the code in Command::InitArguments or fix the ordering so the optional arguments really do come last.