release-23.1: sql: stop ignoring internal exec for sql metrics

[rafiss]

Backport 1/1 commits from #119251.

/cc @cockroachdb/release

Release justification: bug fix

---

There were if-statements that prevented the metrics from being updated. These conditionals were added in
406139e. I confirmed that the test added in that commit still passes after this change, and made the test check that the correct internal metrics are updated.

Epic: None

Release note (bug fix): Fixed a bug that caused the sql.txns.open.internal and sql.statements.active.internal metrics to never get updated. These metrics are gauges that count the number of transactions and statements being executed by operations internal to CockroachDB; they do not include any operations executed by the external SQL client. This bug was present since v22.1.0.

[blathers-crl]

Thanks for opening a backport.

Please check the backport criteria before merging:

• Backports should only be created for serious
  issues or test-only changes.
• Backports should not break backwards-compatibility.
• Backports should change as little code as possible.
• Backports should not change on-disk formats or node communication protocols.
• Backports should not add new functionality (except as defined
  here).
• Backports must not add, edit, or otherwise modify cluster versions; or add version gates.
• All backports must be reviewed by the owning areas TL and one additional
  TL. For more information as to how that review should be conducted, please consult the backport
  policy.

If your backport adds new functionality, please ensure that the following additional criteria are satisfied:

• There is a high priority need for the functionality that cannot wait until the next release and is difficult to address in another way.
• The new functionality is additive-only and only runs for clusters which have specifically “opted in” to it (e.g. by a cluster setting).
• New code is protected by a conditional check that is trivial to verify and ensures that it only runs for opt-in clusters. State changes must be further protected such that nodes running old binaries will not be negatively impacted by the new state (with a mixed version test added).
• The PM and TL on the team that owns the changed code have signed off that the change obeys the above rules.
• Your backport must be accompanied by a post to the appropriate Slack
  channel (#db-backports-point-releases or #db-backports-XX-X-release) for awareness and discussion.

Also, please add a brief release justification to the body of your PR to justify this
backport.

[cockroach-teamcity]

This change is 

[yuzefovich]

Reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @mgartner and @rafiss)

---

pkg/sql/conn_executor_test.go line 1579 at r1 (raw file):

	s, sqlDB, _ := serverutils.StartServer(t, params)
	defer s.Stopper().Stop(ctx)
	defer sqlDB.Close()

nit: just FYI: I think closing the connection is unnecessary since s.Stopper().Stop() should do it.