release-24.1: workload/schemachange: support UDFs invoking other UDFs

[blathers-crl]

Backport 2/2 commits from #121219 on behalf of @fqazi.

/cc @cockroachdb/release

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This patch adds support for the schema change workload to create UDF's which invoke other UDF's, which will need the following:

1. Extend pg_depend to support tracking UDF references to other UDFs. This is an extension from Postgres behaviour where classid will refer to the pg_proc table.
2. Update the schema changer workload to create include UDF references when creating functions
3. Modify the schema changer workload to ensure that DROP / RENAME FUNCTION operations on these functions check for references to other functions, which will cause the operation to fail.
4. Modify the schema changer workload to ensure that DROP SCHEMA with the legacy schema changer will properly block operations if references exist from a different schema.

Fixes: #120671

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Release justification: test change

[blathers-crl]

Thanks for opening a backport.

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[cockroach-teamcity]

This change is