monitoringdashboard: add support for xyChart dataSets.targetAxis and y2Axis

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This pull-request has been approved by: yuwenma

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[yuwenma]

/lgtm

[justinsb]

I'm a little worried that this one is failing because of server-side defaulting causing a diff (on the y1Axis, I think), hence #2169

[justinsb]

/hold

The http log is suspicious here...

[justinsb]

/hold cancel

I reviewed the full http.log; it looks right. The diff is confusing though!

[yuwenma]

/hold cancel

I reviewed the full http.log; it looks right. The diff is confusing though!

Do you mean the timeSeriesTable? Agree it's confusing. I think that code is actually merged https://github.com/GoogleCloudPlatform/k8s-config-connector/blob/b5a5611408a8949faae46c2a9744dad4814125b8/pkg/test/resourcefixture/testdata/basic/monitoring/v1beta1/monitoringdashboard/monitoringdashboardfull/_http.log#L784-L809

[yuwenma]

/lgtm