Fix Brevo list_modules pagination to return all lists

[matiasqueroceballos]

Problem
The fc_crm_module dropdown in Contact Form 7 (and other form plugins) only displayed 10 lists from Brevo, even though the account had 87 lists. The API response showed count: 87, confirming all lists existed but weren't being fetched.

Root Cause
The api() method in CRMLIB_Brevo had three chained bugs in its GET pagination logic:

Missing URL parameters: Query string params ?limit=N&offset=N were commented out, so every API request hit the same endpoint without pagination parameters. Brevo defaults to 10 items when no limit is specified.

Loop never repeats: The repeat_query condition compared count($result['data']) (which was 10) against a hardcoded $limit of 100, causing the loop to exit after one iteration.

Broken data accumulation: The method tried to merge entire response envelopes ({lists: [...], count: 87}) instead of just the nested items array, then list_modules() looked for ['data']['lists'] in a structure that no longer had that nesting.

Solution
Modified /includes/crm-library/class-crmlib-brevo.php:

In api() GET block:

Append ?limit=50&offset=N to the URL for each request
Extract nested items ($result['data']['lists']) from the response, or fall back to $result['data'] if not nested
Accumulate only items (not envelopes) in $result_data
Use $offset < $total to control pagination loop continuation
In list_modules():

Read $result_lists['data'] directly as a flat array (changed from $result_lists['data']['lists'])
Impact
✅ Dropdown now displays all 87 lists instead of 10
✅ Backwards compatible: Other Brevo endpoints like contacts/attributes continue working because the extraction logic safely detects nested vs flat responses
✅ Pagination now works for any endpoint with paginated results
Testing
Open Contact Form 7 with Brevo connected
Navigate to CRM settings
Verify CRM Module dropdown shows all 87 lists (scroll through dropdown)
Verify field mapping still works (check that custom fields load correctly)