sql: show ttl_job_cron if ttl_job_cron is not explicitly set

[otan]

Resolves #80215

Release note (sql change): ttl_job_cron is now displayed on SHOW CREATE
TABLE and reloptions by default.

[cockroach-teamcity]

This change is 

[rafiss]

nice!

Reviewed 8 of 8 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @otan)

[rafiss]

simple test fix needed:

=== RUN   TestDataDriven/row_level_ttl
    datadriven_test.go:304:
        /go/src/github.com/cockroachdb/cockroach/pkg/ccl/backupccl/testdata/backup-restore/row_level_ttl:35: SELECT create_statement FROM [SHOW CREATE TABLE d.public.t]
        output didn't match expected:
        @@ -1,6 +1,6 @@
         CREATE TABLE public.t (
           id INT8 NOT NULL,
           crdb_internal_expiration TIMESTAMPTZ NOT VISIBLE NOT NULL DEFAULT current_timestamp():::TIMESTAMPTZ + '00:10:00':::INTERVAL ON UPDATE current_timestamp():::TIMESTAMPTZ + '00:10:00':::INTERVAL,
           CONSTRAINT t_pkey PRIMARY KEY (id ASC)
        -) WITH (ttl = 'on', ttl_automatic_column = 'on', ttl_expire_after = '00:10:00':::INTERVAL)
        +) WITH (ttl = 'on', ttl_automatic_column = 'on', ttl_expire_after = '00:10:00':::INTERVAL, ttl_job_cron = '@hourly')

[otan]

bors r=rafiss

[craig]

Build succeeded:

• GitHub CI (Cockroach)