[merr1988]

Part 2 of b/576454554, after #560.

Problem

Pull fetched each entry with only the aspect types catalog.yaml lists and its entry type requires, so it could not say what it left out. With a catalog.yaml from before #560, a knowledge base document pulls with an empty body and kcmd is silent.

Change

• Pull reads each entry with the aspect types it knows, as before, and stores that result.
• A second read per entry, CatalogClient.lookupEntryAspectTypes, reads the FULL view's keys alone and names each aspect type on the entry once, with project numbers resolved. A FULL read gives data only to the aspects the entry's type requires, so pull cannot store from it.
• Pull warns once per aspect type the first read did not return, it does not know and the scope does not list as a system aspect:
  Warning: pull left out aspect type 'X' on N entries; list it under snapshot.aspects in catalog.yaml to pull it.
• CatalogSource.systemAspects: aspects the service writes beyond the required ones, left out without a warning. BigQuery dataset: bigquery-policy, data-profile, data-quality-scorecard and usage.
• One helper reads an aspect key's type for _fixEntry and the new method.

Tests

• New pull_left_out scenario: two entries with an unlisted aspect and one with overview, pulled with a catalog.yaml that lists none. Nothing extra is stored, and pull warns once per type with the entry count.
• pull_bq: a table with usage and bigquery-policy pulls without them and with no warning.
• The scenario harness records console.warn and checks assert.warnings.
• The catalog mock matches Dataplex: lookupEntry returns only the requested aspects, and lookupEntryAspectTypes every aspect type on the entry.
• lookupEntryAspectTypes reads the FULL view and names each type once, with a project ID, looking up each type's project once.
• Mutation checks: dropping usage fails pull_bq; removing the warning or the second read fails pull_left_out.
• tsc clean; scenarios 24, layouts 2, gcp 13, semantic 2076, tool 421, all pass.

[feixufeixu]

Approving with two required fixes. In production a FULL read returns data only for the aspects an entry's type requires. So this pull stops storing the overview that #560 lists, and the new warning never prints. My sync.ts comment gives the fix, and my mocks.ts comment covers why the tests still pass. The other two comments are optional.