Reject page_size < 1 and csv/tsv records_format in get_datastore_records

[mcarans]

get_datastore_records now raises HDXError for two inputs it cannot handle:

• page_size below 1. With page_size=0, CKAN returns no records and the loop check 0 < 0 is false, so it requests offset 0 forever. On stage, it was stopped after 10 identical calls.
• records_format csv or tsv. CKAN returns records as a single string for these formats, so yield from records yields single characters and len(records) counts characters, not rows. On stage, a 27-row resource with page_size=10 yielded 7,795 characters. search_datastore handles these formats correctly and remains the way to get them.

Both errors are raised on the first iteration, since the method is a generator. Neither case worked before, so no working caller is affected. The docstring and documentation/index.md note the csv/tsv restriction.

[github-actions]

Test Results

180 tests  ±0   180 ✅ ±0   1m 15s ⏱️ -20s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 32b5932. ± Comparison against base commit 6832186.

♻️ This comment has been updated with latest results.

[coveralls]

coverage: 97.259% (+0.004%) from 97.255% — datastore-records-arg-validation into main