Create campaign in bulk

This endpoint creates multiple campaigns simultaneously (up to 1,000) based on the specified campaign type. Use it to submit a single request containing different campaign types and configurations. The endpoint supports CAMPAIGN_TYPE_DISPLAY, CAMPAIGN_TYPE_BANNERX, and CAMPAIGN_TYPE_BANNER, each with its own type-specific validation. Note: For CAMPAIGN_TYPE_BANNER, the bannerConfig field must be provided. For CAMPAIGN_TYPE_BANNERX, the bannerXConfig field must be provided.