Add dailyBudget and budgetOptimization fields to campaign_groups stream (LinkedIn Ads source)

[Chris van den Hurk (sun-cv)]

Problem / Current Behavior

The campaign_groups stream in the LinkedIn Ads source connector only exposes totalBudget. For accounts using Campaign Group Budget Optimization (budgetOptimizationStrategy = DYNAMIC in LinkedIn's API), budget is managed entirely at the campaign-group level rather than per-campaign. In that setup, individual campaigns report dailyBudget and totalBudget as null, and the campaign group's own dailyBudget is also not synced because it isn't in the connector's schema making budget data invisible through Airbyte for these accounts. This is an increasingly common configuration since LinkedIn defaults new accounts toward group-level budget optimization.

Requested Enhancement

1. Bump the Linkedin-Version header used by the campaign_groups stream to >= 202504.
2. Add dailyBudget (amount/currencyCode) and the budgetOptimization object (bidStrategy, budgetOptimizationStrategy) to the campaign_groups stream schema.

Use Case

Teams that rely on LinkedIn's Campaign Group Budget Optimization need budget figures to build accurate spend and pacing reports in their warehouse. Without these fields, budget data has to be tracked and reconciled manually outside of Airbyte.

Additional Context

LinkedIn Marketing API reference: Create and Manage Campaign Groups. Per the docs, dailyBudget applies to API versions 202504+; budgetOptimization.bidStrategy / budgetOptimization.budgetOptimizationStrategy apply to 202501+.