Add support for private options in DSR queries

[j4james]

The original implementation of the Device Status Report sequence was
only capable of handling ANSI status queries. This PR adds the ability
to respond to private DEC queries as well.

To prove it's working as intended, I've also included support for the
DEC extended cursor position report (DECXCPR), which is essentially
the same as the ANSI cursor position report, but with an additional
parameter indicating the page number. Until we support paging, though,
that value is just hardcoded to 1.

References

The method for distinguishing between ANSI options and the private DEC
options is based on the updates made to the SM/RM mode sequences in
PR #8469.

Validation Steps Performed

I've added a couple of unit tests covering the DECXCPR report, and
also manually confirmed we now pass the Extended Cursor-Position test
in vttest.

Closes #14206

[DHowett]

Ah, was this causing trouble? Sorry!

[j4james]

Yeah, that was a bit confusing. I couldn't figure out why it would suddenly have a problem with that, but when Flag is 0 that doesn't count as a single bit. I'm assuming it didn't complain before because we hadn't actually used the ANSI modes yet.

[carlos-zamora]

@msftbot merge this in 10 minutes

[ghost]

Hello @carlos-zamora!

Because you've given me some instructions on how to help merge this pull request, I'll be modifying my merge approach. Here's how I understand your requirements for merging this pull request:

• I won't merge this pull request until after the UTC date Tue, 25 Oct 2022 18:40:01 GMT, which is in 10 minutes

If this doesn't seem right to you, you can tell me to cancel these instructions and use the auto-merge policy that has been configured for this repository. Try telling me "forget everything I just told you".

[ghost]

🎉Windows Terminal Preview v1.17.1023 has been released which incorporates this pull request.:tada:

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