pkg/util/log: remove stderr config code for deprecated log format

Code used to validate the stderr config parsing previously checked to
see if the `crdb-v1-tty` format was being used when `auditable: true`
was set. If it was, it changed the format to `crdb-v1-tty-count`.

However, the `crdb-v1` log formats have long been deprecated, and the
official logging documentation states:

https://www.cockroachlabs.com/docs/stable/configure-logs#output-to-stderr
> Note: The `format` parameter for `stderr` is set to `crdb-v2-tty` and
cannot be changed.

Given this, it not longer makes sense to have code that accounts for a
stderr log format that's no longer valid. Instead, we should *always*
assert the format to be `crdb-v2-tty` to align with what our
documentation says. A following patch will add this assertion.

Release note: none

pkg/util/log/logconfig/validate.go

@@ -172,10 +172,6 @@ func (c *Config) Validate(defaultLogDir *string) (resErr error) {
 	}
 	propagateCommonDefaults(&c.Sinks.Stderr.CommonSinkConfig, c.FileDefaults.CommonSinkConfig)
 	if c.Sinks.Stderr.Auditable != nil && *c.Sinks.Stderr.Auditable {
-		if *c.Sinks.Stderr.Format == "crdb-v1-tty" {
-			f := "crdb-v1-tty-count"
-			c.Sinks.Stderr.Format = &f
-		}
 		c.Sinks.Stderr.Criticality = &bt
 	}
 	c.Sinks.Stderr.Auditable = nil