kvserver: Fix WAL Bytes Written Metrics

[raggar]

Currently the number of WAL bytes written does not show up. This pr fixes that by using a consistent metric name.

Informs: #104531
Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[jbowens]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @RahulAggarwal1016)

---

pkg/kv/kvserver/metrics.go line 2037 at r1 (raw file):

	}
	metaWALBytesWritten = metric.Metadata{
		Name:        "storage.wal.bytes_written",

Let's update the graph to use this metric name, not the other way around. We no longer use RocksDB, so we don't want to introduce new metrics that use the rocksdb name.

[jbowens]

Reviewed 1 of 2 files at r2, 1 of 1 files at r3, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @RahulAggarwal1016)

[raggar]

bors r+

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)