Add support for the HPA escape sequence

[j4james]

Summary of the Pull Request

HPA (horizontal position absolute) is just an alias for the existing CHA (cursor horizontal absolute) escape sequence, which moves the cursor position to the specified column on the current line. This is needed in order to pass the HPA test in Vttest.

PR Checklist

• Closes Add support for the HPA escape sequence #3348
• CLA signed. If not, go over here and sign the CLA
• Tests added/passed
• Requires documentation to be updated
• I've discussed this with core contributors already. If not checked, I'm ready to accept this work might be rejected in favor of a different grand plan. Issue number where discussion took place: Add support for the HPA escape sequence #3348

Detailed Description of the Pull Request / Additional comments

As discussed in issue #3348, the general consensus is that this can be considered an alias for the CHA escape sequence. So I've just added a new entry in the VTActionCodes enum for the HPA final character, and then updated the switch statements in OutputStateMachineEngine::ActionCsiDispatch to share the same code path as the existing CHA action.

I haven't bothered with giving it a unique telemetry code, since we haven't done that for the CUP and HVP codes either, so I assumed that would be OK.

Validation Steps Performed

I've extended the existing output engine tests for CSI cursor movement to confirm that HPA is dispatched in the same way as CHA. I've also checked the HPA test in Vttest (under Test non-VT100 / ISO-6429 cursor-movement) and confirmed that it is now working as expected.

[DHowett-MSFT]

Looks good to me!

[zadjii-msft]

Looks like a convenient easy change. Thanks!

[ghost]

🎉Windows Terminal Preview v0.7.3291.0 has been released which incorporates this pull request.:tada:

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