Add Two Counter Metric in BigQuery Write Schema Transform

[nickuncaged1201]

Adding two metrics, an input PCollection element count and one write failure count in BigQuery write schema transform. The metrics will be used for Syndeo monitoring integration.

[nickuncaged1201]

r: @pabloem
r: @manavgarg

[pabloem]

this seems reasonable. We may add more metrics to the elm/err counter, but we're good as-is for now, huh?

[pabloem]

LGTM. LMK if we should merge

[nickuncaged1201]

I'll probably change the name of each counter to be more descriptive of the IO type they are instrumented for. But that can wait till I add in Pub/Sub read metrics and I'll make the change. Think this is good for now. Feel free to merge it if you think It's okay!

Thanks @pabloem for all the suggestion!

[nickuncaged1201]

@pabloem kindly pinging here to see if it's okay to merge this PR

[pabloem]

Run Java_GCP_IO_Direct PreCommit

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[pabloem]

lgtm thanks @nickuncaged1201 !