Forked from #48123.

Describe the problem

The test TestSpanAssembler in sql/colexec/colexecspan/span_assembler_test.go currently uses keys.TODOSQLCodec.

This means that it does not currently exercise secondary tenant keyspans.

Expected behavior

The test should be modified to contain two sub-tests, one using the system tenant codec and one for a secondary tenant.

cc @rharding6373 @yuzefovich for triage.

Jira issue: CRDB-16711