ui: initial load of table list takes minutes (!) when there are 10000+ tables in db

[knz]

(Found via #94027)

Describe the problem

When there are 10000+ tables in a single db, the initial display of the table list takes 30+ seconds, leaving the user to wonder if something is broken.

To Reproduce

1. start cockroach demo with the changes from sql: new functions crdb_internal.generate_test_objects and .gen_rand_ident #94027
2. generate 10000 tables, e.g. via select crdb_internal.generate_test_objects('{"counts":[10000],"name_gen":{"noise":false}}'::jsonb);
3. navigate to db console -> defaultdb eg. via http://127.0.0.1:8080/#/database/defaultdb

Observe: the page remains blank for very long.

Expected behavior

The first page of results should display immediately.

Additional data / screenshots

Environment:

• master towards v23.1

Epic: CRDB-20388

Jira issue: CRDB-22835